fixup! [RFC-0010] Add multi-tenant workload identity support for AWS Bucket

Remove os.Setenv() to prevent env var pollution

Remove os.Setenv() call that could cause environment variable
pollution in multi-tenant environments. The pkg/auth/aws package
already handles region configuration properly by prioritizing
opts.STSRegion over AWS_REGION environment variable.

Signed-off-by: cappyzawa <cappyzawa@gmail.com>

Author: cappyzawa

internal/bucket/minio/minio.go

@@ -23,7 +23,6 @@ import (
 	"fmt"
 	"net/http"
 	"net/url"
-	"os"
 	"strings"
 
 	"github.com/minio/minio-go/v7"
@@ -188,11 +187,6 @@ func newAWSCreds(ctx context.Context, o *options) (*credentials.Credentials, err
 	var opts auth.Options
 	opts.Apply(o.authOpts...)
 
-	// Set AWS_REGION environment variable from bucket.Spec.Region for pkg/auth/aws
-	if opts.STSRegion != "" {
-		os.Setenv("AWS_REGION", opts.STSRegion)
-	}
-
 	awsCredsProvider := awsauth.NewCredentialsProvider(ctx, o.authOpts...)
 	awsCreds, err := awsCredsProvider.Retrieve(ctx)
 	if err != nil {