fix: use old dockerfile

Dockerfile

@@ -1,11 +1,4 @@
-ARG GO_VERSION=1.23
-ARG XX_VERSION=1.6.1
-
-FROM --platform=$BUILDPLATFORM tonistiigi/xx:${XX_VERSION} AS xx
-FROM --platform=$BUILDPLATFORM golang:${GO_VERSION}-alpine AS builder
-
-# copy build utilities
-COPY --from=xx / /
+FROM golang:1.23-alpine as builder
 
 ARG TARGETPLATFORM
 ARG REVISON
@@ -24,10 +17,9 @@ COPY cmd/ cmd/
 COPY pkg/ pkg/
 
 # build
-ENV CGO_ENABLED=0
-RUN xx-go build \
-    -ldflags "-s -w -X github.com/fluxcd/flagger/pkg/version.REVISION=${REVISON}" \
-    -a -o flagger ./cmd/flagger
+RUN CGO_ENABLED=0 go build \
+  -ldflags "-s -w -X github.com/fluxcd/flagger/pkg/version.REVISION=${REVISON}" \
+  -a -o flagger ./cmd/flagger
 
 FROM alpine:3.21