### 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_
if config.LAMBDA_DOCKER_FLAGS:
            inv_context.docker_flags = (
                f"{config.LAMBDA_DOCKER_FLAGS} {inv_context.docker_flags or ''}".strip()
            )
        event_stdin_bytes = stdin_str and to_bytes(stdin_str)
        error = None
        try:
            result, log_output = self.execute_in_container(
                lambda_function,
                inv_context,
                stdin=event_stdin_bytes,
            )
        except ContainerException as e:
            result = e.stdout or ""
            log_output = e.stderr or ""
            error = e
        except InvocationException as e:
            result = e.result or ""
            log_output = e.log_output or ""
            error = e
        try:
            result = to_str(result).strip()
        except Exception:
            pass
        log_output = to_str(log_output).strip()
        
        
        
        if isinstance(result, str) and "\n" in result:
            lines = result.split("\n")