### 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_
FunctionName=function_name,
            MaximumRetryAttempts=1,
        )
        snapshot.match("put_function_event_invoke_config_maxattempt1", response)
        
        lambda_client.delete_function_event_invoke_config(FunctionName=function_name)
    def test_function_concurrency(self, lambda_client, create_lambda_function, snapshot):
        """Testing the api of the put function concurrency action"""
        snapshot.add_transformer(snapshot.transform.lambda_api())
        function_name = f"lambda_func-{short_uid()}"
        create_lambda_function(
            handler_file=TEST_LAMBDA_PYTHON_ECHO,
            func_name=function_name,
            runtime=LAMBDA_RUNTIME_PYTHON36,
        )
        
        
        response = lambda_client.put_function_concurrency(
            FunctionName=function_name, ReservedConcurrentExecutions=123
        )
        snapshot.match("put_function_concurrency", response)
        assert "ReservedConcurrentExecutions" in response
        response = lambda_client.get_function_concurrency(FunctionName=function_name)
        snapshot.match("get_function_concurrency", response)
        assert "ReservedConcurrentExecutions" in response
        lambda_client.delete_function_concurrency(FunctionName=function_name)
    @pytest.mark.skip_snapshot_verify
    def test_function_code_signing_config(self, lambda_client, create_lambda_function, snapshot):
        """Testing the API of code signing config"""
        snapshot.add_transformer(snapshot.transform.lambda_api())