### 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_
super(LambdaExecutorSeparateContainers, self).__init__()
        self.max_port = LAMBDA_API_UNIQUE_PORTS
        self.port_offset = LAMBDA_API_PORT_OFFSET
    def prepare_event(self, environment: Dict, event_body: str) -> bytes:
        
        environment["DOCKER_LAMBDA_USE_STDIN"] = "1"
        return event_body.encode()
    def execute_in_container(
        self,
        lambda_function: LambdaFunction,
        inv_context: InvocationContext,
        stdin=None,
        background=False,
    ) -> Tuple[bytes, bytes]:
        docker_image = Util.docker_image_for_lambda(lambda_function)
        container_config = LambdaContainerConfiguration(image_name=docker_image)
        container_config.env_vars = inv_context.environment
        if inv_context.lambda_command:
            container_config.entrypoint = ""
        elif inv_context.handler:
            inv_context.lambda_command = inv_context.handler
        
        container_config.network = get_container_network_for_lambda()
        if container_config.network == "host":
            port = get_free_tcp_port()