### 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_
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.create_code_signing_config(
            Description="Testing CodeSigning Config",
            AllowedPublishers={
                "SigningProfileVersionArns": [
                    f"arn:aws:signer:{aws_stack.get_region()}:000000000000:/signing-profiles/test",
                ]
            },
            CodeSigningPolicies={"UntrustedArtifactOnDeployment": "Enforce"},
        )
        snapshot.match("create_code_signing_config", response)
        assert "Description" in response["CodeSigningConfig"]
        assert "SigningProfileVersionArns" in response["CodeSigningConfig"]["AllowedPublishers"]
        assert (
            "UntrustedArtifactOnDeployment" in response["CodeSigningConfig"]["CodeSigningPolicies"]
        )
        code_signing_arn = response["CodeSigningConfig"]["CodeSigningConfigArn"]
        response = lambda_client.update_code_signing_config(
            CodeSigningConfigArn=code_signing_arn,
            CodeSigningPolicies={"UntrustedArtifactOnDeployment": "Warn"},
        )
        snapshot.match("update_code_signing_config", response)
        assert (
            "Warn"
            == response["CodeSigningConfig"]["CodeSigningPolicies"]["UntrustedArtifactOnDeployment"]