Upgrade AWS SDK Go to v2

Although aws-sdk-go-v2 was released long ago, historically, until now,
tfmigrate has used v1 as well as the old Terraform.

aws-sdk-go and aws-sdk-go-v2 have different priorities for loading
credentials. Specifically, aws-sdk-go v1 prioritizes reading environment
variables over profiles. This is a problem when switching between
multiple accounts in a profile while OIDC authenticating to AWS from
GitHub Actions.

Up to Terraform v1.5, aws-sdk-go v1 was used for S3 backend
authentication via hashicorp/aws-sdk-go-base, but aws-sdk-go-v2 is used
for Terraform / OpenTofu v1.6 and later.

Up to tfmigrate v0.3, we have been using aws-sdk-go v1 via
hashicorp/aws-sdk-go-base for history s3 storage authentication but will
be using aws-sdk-go-v2 after the next tfmigrate v0.4. This is a breaking
change, but the goal is to align with the behavior of Terraform /
OpenTofu v1.6 and later, so if you are affected, please adjust your AWS
authentication settings.

At the time of this writing, v2 of hashicorp/aws-sdk-go-base, which uses
aws-sdk-go-v2, is still beta, but it is already used in the stable
releases of Terraform and OpenTofu. Since there are multiple beta
versions of hashicorp/aws-sdk-go-base and slightly different versions in
use, the results of my investigation are shown below.

- tfmigrate: v0.3.24: v1.1.0
- terraform v1.5.7: v0.7.1
- terraform v1.6.0: v2.0.0-beta.35
- terraform v1.7.0: v2.0.0-beta.43
- terraform v1.8.0: v2.0.0-beta.45
- terraform v1.9.8 (latest): v2.0.0-beta.45
- opentofu v1.6.0: v2.0.0-beta.43
- opentofu v1.8.5 (latest): v2.0.0-beta.43
- terraform-provider-aws v3.76.1: v1.0.0
- terraform-provider-aws v4.0.0: v2.0.0-beta.5
- terraform-provider-aws v5.0.0: v2.0.0-beta.27
- terraform-provider-aws v5.29.0: v2.0.0-beta.43
- terraform-provider-aws v5.31.0: v2.0.0-beta.45
- terraform-provider-aws v5.74.0 (latest): v2.0.0-beta.59

As a special note, use_legacy_workflow has been removed in Terraform
v1.8.0 and OpenTofu v1.8.0, but UseLegacyWorkflow has been removed in
aws-sdk-go-base in v2.0.0-beta.49.

Considering the above, I think v2.0.0-beta.43 or v2.0.0-beta.45 would be
reasonable. However, at this point, I don't see any solid reason for
choosing v2.0.0-beta.45, so I will select v2.0.0-beta.43 to align with
OpenTofu.

I rewrote the s3 implementation for history storage, referring to the
aws-sdk-go-v2 migration guide.

https://aws.github.io/aws-sdk-go-v2/docs/migrating/

From the tfmigrate user's perspective, there are no breaking changes at
the configuration file level. Still, it should be noted that AWS
credentials have higher precedence in profiles than in environment
variables.

Also, as a notable side effect of the upgrade to v2, the path to the
file configuring the AWS profile is ~/.aws/config by default, but it can
now be specified in the environment variable AWS_CONFIG_FILE. This will
be useful for customizing the configuration in a CI/CD environment.

go.mod

@@ -4,10 +4,15 @@ go 1.22
 
 require (
 	cloud.google.com/go/storage v1.36.0
-	github.com/aws/aws-sdk-go v1.55.5
+	github.com/aws/aws-sdk-go-v2 v1.32.3
+	github.com/aws/aws-sdk-go-v2/config v1.28.1
+	github.com/aws/aws-sdk-go-v2/credentials v1.17.42
+	github.com/aws/aws-sdk-go-v2/feature/ec2/imds v1.16.18
+	github.com/aws/aws-sdk-go-v2/feature/s3/manager v1.17.35
+	github.com/aws/aws-sdk-go-v2/service/s3 v1.66.2
 	github.com/davecgh/go-spew v1.1.1
 	github.com/google/go-cmp v0.6.0
-	github.com/hashicorp/aws-sdk-go-base v1.1.0
+	github.com/hashicorp/aws-sdk-go-base/v2 v2.0.0-beta.43
 	github.com/hashicorp/go-version v1.3.0
 	github.com/hashicorp/hcl/v2 v2.6.0
 	github.com/hashicorp/logutils v1.0.0
@@ -26,8 +31,25 @@ require (
 	github.com/apparentlymart/go-textseg v1.0.0 // indirect
 	github.com/apparentlymart/go-textseg/v12 v12.0.0 // indirect
 	github.com/armon/go-radix v0.0.0-20180808171621-7fddfc383310 // indirect
+	github.com/aws/aws-sdk-go-v2/aws/protocol/eventstream v1.6.6 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/configsources v1.3.22 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/endpoints/v2 v2.6.22 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/ini v1.8.1 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/v4a v1.3.22 // indirect
+	github.com/aws/aws-sdk-go-v2/service/dynamodb v1.25.5 // indirect
+	github.com/aws/aws-sdk-go-v2/service/iam v1.27.5 // indirect
+	github.com/aws/aws-sdk-go-v2/service/internal/accept-encoding v1.12.0 // indirect
+	github.com/aws/aws-sdk-go-v2/service/internal/checksum v1.4.3 // indirect
+	github.com/aws/aws-sdk-go-v2/service/internal/endpoint-discovery v1.8.5 // indirect
+	github.com/aws/aws-sdk-go-v2/service/internal/presigned-url v1.12.3 // indirect
+	github.com/aws/aws-sdk-go-v2/service/internal/s3shared v1.18.3 // indirect
+	github.com/aws/aws-sdk-go-v2/service/sqs v1.28.4 // indirect
+	github.com/aws/aws-sdk-go-v2/service/sso v1.24.3 // indirect
+	github.com/aws/aws-sdk-go-v2/service/ssooidc v1.28.3 // indirect
+	github.com/aws/aws-sdk-go-v2/service/sts v1.32.3 // indirect
+	github.com/aws/smithy-go v1.22.0 // indirect
 	github.com/bgentry/speakeasy v0.1.0 // indirect
-	github.com/fatih/color v1.7.0 // indirect
+	github.com/fatih/color v1.15.0 // indirect
 	github.com/felixge/httpsnoop v1.0.4 // indirect
 	github.com/go-logr/logr v1.4.1 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
@@ -37,22 +59,25 @@ require (
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/googleapis/enterprise-certificate-proxy v0.3.2 // indirect
 	github.com/googleapis/gax-go/v2 v2.12.0 // indirect
-	github.com/hashicorp/errwrap v1.0.0 // indirect
-	github.com/hashicorp/go-cleanhttp v0.5.0 // indirect
-	github.com/hashicorp/go-multierror v1.0.0 // indirect
+	github.com/hashicorp/errwrap v1.1.0 // indirect
+	github.com/hashicorp/go-hclog v1.5.0 // indirect
+	github.com/hashicorp/go-multierror v1.1.1 // indirect
+	github.com/hashicorp/terraform-plugin-log v0.9.0 // indirect
 	github.com/jmespath/go-jmespath v0.4.0 // indirect
-	github.com/mattn/go-colorable v0.0.9 // indirect
-	github.com/mattn/go-isatty v0.0.3 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.17 // indirect
 	github.com/mitchellh/go-homedir v1.1.0 // indirect
 	github.com/mitchellh/go-wordwrap v0.0.0-20150314170334-ad45545899c7 // indirect
 	github.com/posener/complete v1.1.1 // indirect
 	go.opencensus.io v0.24.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/github.com/aws/aws-sdk-go-v2/otelaws v0.46.1 // indirect
 	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.47.0 // indirect
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.47.0 // indirect
 	go.opentelemetry.io/otel v1.22.0 // indirect
 	go.opentelemetry.io/otel/metric v1.22.0 // indirect
 	go.opentelemetry.io/otel/trace v1.22.0 // indirect
 	golang.org/x/crypto v0.22.0 // indirect
+	golang.org/x/exp v0.0.0-20230905200255-921286631fa9 // indirect
 	golang.org/x/net v0.24.0 // indirect
 	golang.org/x/oauth2 v0.17.0 // indirect
 	golang.org/x/sync v0.6.0 // indirect