### 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_
result = lambda_client.invoke(FunctionName=function_name, Payload=data_before)
        result = read_streams(result)
        snapshot.match("invocation-response", result)
        data_after = json.loads(result["Payload"])
        assert json.loads(to_str(data_before)) == data_after["event"]
        context = data_after["context"]
        assert "$LATEST" == context["function_version"]
        assert function_name == context["function_name"]
        
        lambda_client.delete_function(FunctionName=function_name)
    @parametrize_python_runtimes
    def test_handler_in_submodule(self, lambda_client, create_lambda_function, runtime):
        """Test invocation of a lambda handler which resides in a submodule (= not root module)"""
        function_name = f"test-function-{short_uid()}"
        zip_file = testutil.create_lambda_archive(
            load_file(TEST_LAMBDA_PYTHON),
            get_content=True,
            libs=TEST_LAMBDA_LIBS,
            runtime=runtime,
            file_name="localstack_package/def/main.py",
        )
        create_lambda_function(
            func_name=function_name,
            zip_file=zip_file,
            handler="localstack_package.def.main.handler",
            runtime=runtime,
        )
        
        result = lambda_client.invoke(FunctionName=function_name, Payload=b"{}")
        result_data = json.loads(result["Payload"].read())