### 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_
create_lambda_function(
            handler_file=TEST_LAMBDA_PYTHON_ECHO,
            func_name=function_name,
            runtime=LAMBDA_RUNTIME_PYTHON36,
        )
        
        action = "lambda:InvokeFunction"
        principal = "s3.amazonaws.com"
        statement_ids = ["s4", "s5"]
        for sid in statement_ids:
            resp = lambda_client.add_permission(
                FunctionName=function_name,
                Action=action,
                StatementId=sid,
                Principal=principal,
                SourceArn=aws_stack.s3_bucket_arn("test-bucket"),
            )
            assert "Statement" in resp
        
        
        policies = iam_client.list_policies(Scope="Local", MaxItems=500)["Policies"]
        policy_name = get_lambda_policy_name(function_name)
        matching = [p for p in policies if p["PolicyName"] == policy_name]
        assert 1 == len(matching)
        assert ":policy/" in matching[0]["Arn"]
        
        policy = matching[0]
        versions = iam_client.list_policy_versions(PolicyArn=policy["Arn"])["Versions"]
        assert 1 == len(versions)
        statements = versions[0]["Document"]["Statement"]