When PUTting an S3 object to Localstack with attached Metadata, if a key contains an underscore it is replaced with a dash.

However, when the same request is performed against the real S3, the key is not modified.

Example Input:
key_with_underscores => test

Localstack Result:
key-with-underscores => test

S3 Result:
key_with_underscores => test

Localstack Version: 0.10.5

Tested using AWS v2 S3 client
bucket = 'test-bucket-%s' % short_uid()
        s3_client = aws_stack.connect_to_service('s3')
        s3_client.create_bucket(Bucket=bucket)
        s3_client.put_bucket_cors(
            Bucket=bucket,
            CORSConfiguration={
                'CORSRules': [{'AllowedMethods': ['GET', 'POST', 'PUT', 'DELETE'],
                               'AllowedOrigins': ['localhost']}]
            }
        )
        response = s3_client.get_bucket_cors(Bucket=bucket)
        self.assertEqual(response['ResponseMetadata']['HTTPStatusCode'], 200)
        
        s3_client.delete_bucket(Bucket=bucket)
    def test_s3_uppercase_names(self):
        
        bucket_name = 'TestBucket-%s' % short_uid()
        self.s3_client.create_bucket(Bucket=bucket_name)
        
        object_key = 'camelCaseKey'
        self.s3_client.put_object(Bucket=bucket_name, Key=object_key, Body='something')
        self.s3_client.get_object(Bucket=bucket_name, Key=object_key)
        self.assertRaises(Exception, self.s3_client.get_object, Bucket=bucket_name, Key=object_key.lower())
    def test_s3_get_response_headers(self):