### 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_
runtime=runtime,
            handler="lambda_handler.handler",
        )
        test_string = "test_string' with some quotes"
        body = f'{{"test_var": "{test_string}"}}'
        rs = lambda_client.invoke(
            FunctionName=function_name,
            Payload=body,
        )
        assert 200 == rs["ResponseMetadata"]["HTTPStatusCode"]
        rs = read_streams(rs)
        snapshot.match("invoke-result", rs)
        response = json.loads(rs["Payload"])
        assert "response from localstack lambda" in response["body"]
        def assert_events():
            events = get_lambda_log_events(function_name, logs_client=logs_client)
            assert len(events) > 0
            assert test_string in str(events[0])
        retry(assert_events, retries=10)
class TestCustomRuntimes:
    @pytest.mark.skipif(
        not use_docker(), reason="Test for docker provided runtimes not applicable if run locally"
    )
    @pytest.mark.parametrize(
        "runtime",
        PROVIDED_TEST_RUNTIMES,
    )
    @pytest.mark.skip_snapshot_verify
    def test_provided_runtimes(
        self, lambda_client, create_lambda_function, runtime, check_lambda_logs, snapshot