### 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_
LAMBDA_RUNTIME_PYTHON39 = "python3.9"
LAMBDA_RUNTIME_NODEJS = "nodejs"
LAMBDA_RUNTIME_NODEJS10X = "nodejs10.x"
LAMBDA_RUNTIME_NODEJS12X = "nodejs12.x"
LAMBDA_RUNTIME_NODEJS14X = "nodejs14.x"
LAMBDA_RUNTIME_JAVA8 = "java8"
LAMBDA_RUNTIME_JAVA8_AL2 = "java8.al2"
LAMBDA_RUNTIME_JAVA11 = "java11"
LAMBDA_RUNTIME_DOTNETCORE2 = "dotnetcore2.0"
LAMBDA_RUNTIME_DOTNETCORE21 = "dotnetcore2.1"
LAMBDA_RUNTIME_DOTNETCORE31 = "dotnetcore3.1"
LAMBDA_RUNTIME_DOTNET6 = "dotnet6"
LAMBDA_RUNTIME_GOLANG = "go1.x"
LAMBDA_RUNTIME_RUBY = "ruby"
LAMBDA_RUNTIME_RUBY25 = "ruby2.5"
LAMBDA_RUNTIME_RUBY27 = "ruby2.7"
LAMBDA_RUNTIME_PROVIDED = "provided"
LAMBDA_RUNTIME_PROVIDED_AL2 = "provided.al2"
LAMBDA_DEFAULT_HANDLER = "handler.handler"
LAMBDA_DEFAULT_RUNTIME = LAMBDA_RUNTIME_PYTHON37
LAMBDA_DEFAULT_STARTING_POSITION = "LATEST"
DOTNET_LAMBDA_RUNTIMES = [
    LAMBDA_RUNTIME_DOTNETCORE2,
    LAMBDA_RUNTIME_DOTNETCORE21,
    LAMBDA_RUNTIME_DOTNETCORE31,
    LAMBDA_RUNTIME_DOTNET6,
]
DOCKER_MAIN_CONTAINER_IP = None
LAMBDA_CONTAINER_NETWORK = None
class ClientError(Exception):