### 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_
TEST_LAMBDA_DOTNETCORE31 = os.path.join(THIS_FOLDER, "functions/dotnetcore31/dotnetcore31.zip")
TEST_LAMBDA_DOTNET6 = os.path.join(THIS_FOLDER, "functions/dotnet6/dotnet6.zip")
TEST_LAMBDA_CUSTOM_RUNTIME = os.path.join(THIS_FOLDER, "functions/custom-runtime")
TEST_LAMBDA_HTTP_RUST = os.path.join(THIS_FOLDER, "functions/rust-lambda/function.zip")
TEST_LAMBDA_JAVA_WITH_LIB = os.path.join(
    THIS_FOLDER, "functions/java/lambda_echo/lambda-function-with-lib-0.0.1.jar"
)
TEST_LAMBDA_JAVA_MULTIPLE_HANDLERS = os.path.join(
    THIS_FOLDER,
    "functions",
    "java",
    "lambda_multiple_handlers",
    "build",
    "distributions",
    "lambda-function-with-multiple-handlers.zip",
)
TEST_LAMBDA_ENV = os.path.join(THIS_FOLDER, "functions/lambda_environment.py")
TEST_LAMBDA_SEND_MESSAGE_FILE = os.path.join(THIS_FOLDER, "functions/lambda_send_message.py")
TEST_LAMBDA_PUT_ITEM_FILE = os.path.join(THIS_FOLDER, "functions/lambda_put_item.py")
TEST_LAMBDA_START_EXECUTION_FILE = os.path.join(THIS_FOLDER, "functions/lambda_start_execution.py")
TEST_LAMBDA_FUNCTION_PREFIX = "lambda-function"
TEST_GOLANG_LAMBDA_URL_TEMPLATE = "https://github.com/localstack/awslamba-go-runtime/releases/download/v{version}/example-handler-{os}-{arch}.tar.gz"
TEST_LAMBDA_LIBS = [
    "requests",
    "psutil",
    "urllib3",
    "chardet",
    "certifi",
    "idna",
    "pip",