aws: fix issue with creating bucket in us-east-1

Region us-east-1 isn't a valid parameter to a createBucket request.
This caused the following error when uploading:

Error:
    uploading variants:
    uploading image:
    ensuring bucket exists:
    creating bucket xxx:
    operation error S3:
    CreateBucket, https response error StatusCode: 400, RequestID: xxx, HostID: xx,
    api error InvalidLocationConstraint:
    The specified location-constraint is not valid

Signed-off-by: Paul Meyer <49727155+katexochen@users.noreply.github.com>

aws/uploader.go

@@ -163,12 +163,19 @@ func (u *Uploader) ensureBucket(ctx context.Context) error {
 		return nil
 	}
 	u.log.Printf("Bucket %s doesn't exist. Creating.", bucket)
-	_, err = s3C.CreateBucket(ctx, &s3.CreateBucketInput{
+	locationConstraint := s3types.BucketLocationConstraint(u.config.AWS.Region)
+	if u.config.AWS.Region == "us-east-1" {
+		// https://docs.aws.amazon.com/AmazonS3/latest/API/API_CreateBucket.html#API_CreateBucket_RequestBody
+		// "If you don't specify a Region, the bucket is created in the US East (N. Virginia) Region (us-east-1)."
+		locationConstraint = s3types.BucketLocationConstraint("")
+	}
+	req := &s3.CreateBucketInput{
 		Bucket: &bucket,
 		CreateBucketConfiguration: &s3types.CreateBucketConfiguration{
-			LocationConstraint: s3types.BucketLocationConstraint(u.config.AWS.Region),
+			LocationConstraint: locationConstraint,
 		},
-	})
+	}
+	_, err = s3C.CreateBucket(ctx, req)
 	if err != nil {
 		return fmt.Errorf("creating bucket %s: %w", bucket, err)
 	}