Replace deplecated function in otelgrpc for go

[yuki0920]

Changes

I replaced deplecated functions with appropriate functions in otelgrpc for go.

In the docs, following functions are deprecated. Instead, NewClientHandler and NewServerHandler shoud be used.

StreamClientInterceptor
StreamServerInterceptor
UnaryClientInterceptor
UnaryServerInterceptor

Merge Requirements

For new features contributions please make sure you have completed the following
essential items:

• CHANGELOG.md updated to document new feature additions
• Appropriate documentation updates in the docs
• Appropriate Helm chart updates in the helm-charts

Maintainers will not merge until the above have been completed. If you're unsure
which docs need to be changed ping the
@open-telemetry/demo-approvers.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: yuki0920 / name: Yuki Watanabe (6e58cc2)