### 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_
@parametrize_python_runtimes
    @pytest.mark.skip_snapshot_verify
    def test_python_runtime_unhandled_errors(
        self, lambda_client, create_lambda_function, runtime, snapshot
    ):
        """Test unhandled errors during python lambda invocation"""
        snapshot.add_transformer(snapshot.transform.lambda_api())
        function_name = f"test_python_executor_{short_uid()}"
        creation_response = create_lambda_function(
            func_name=function_name,
            handler_file=TEST_LAMBDA_PYTHON_UNHANDLED_ERROR,
            runtime=runtime,
        )
        snapshot.match("creation_response", creation_response)
        result = lambda_client.invoke(
            FunctionName=function_name,
            Payload=b"{}",
        )
        result = read_streams(result)
        snapshot.match("invocation_response", result)
        assert result["StatusCode"] == 200
        assert result["ExecutedVersion"] == "$LATEST"
        assert result["FunctionError"] == "Unhandled"
        payload = json.loads(result["Payload"])
        assert payload["errorType"] == "CustomException"
        assert payload["errorMessage"] == "some error occurred"
        assert "stackTrace" in payload
        if (
            runtime == "python3.9" and not is_old_provider()
        ):