### Is there an existing issue for this?

- [X] I have searched the existing issues

### Feature description

The use case I have in mind is to run Node 16.x Lambdas - the default container registry is `lambci/lambda` which is effectively abandoned. [Not even Node 14.x has been published](https://github.com/lambci/docker-lambda/pull/330). However, switching the registry over to [`amazon/aws-lambda-nodejs`](https://hub.docker.com/r/amazon/aws-lambda-nodejs) still fails to pull the container, since localstack is looking for the tag `nodejs16.x`. I'd like to be able to specify that if the runtime is `nodejs16.x` it just looks for tag `16`.

### 🧑‍💻 Implementation

_No response_

### Anything else?

_No response_
rs = sqs_client.receive_message(QueueUrl=queue_url, MessageAttributeNames=["All"])
            assert len(rs["Messages"]) > 0
            return rs["Messages"][0]
        message = retry(receive_message, retries=15, sleep=2)
        assert event["message"] == message["Body"]
    @parametrize_python_runtimes
    def test_lambda_put_item_to_dynamodb(
        self,
        lambda_client,
        create_lambda_function,
        dynamodb_create_table,
        runtime,
        dynamodb_resource,
        lambda_su_role,
        dynamodb_client,
    ):
        """Put item into dynamodb from python lambda"""
        table_name = f"ddb-table-{short_uid()}"
        function_name = f"test-function-{short_uid()}"
        dynamodb_create_table(table_name=table_name, partition_key="id")
        create_lambda_function(
            handler_file=TEST_LAMBDA_PUT_ITEM_FILE,
            func_name=function_name,
            runtime=runtime,
            role=lambda_su_role,
        )
        data = {short_uid(): f"data-{i}" for i in range(3)}
        event = {
            "table_name": table_name,
            "region_name": dynamodb_client.meta.region_name,