### 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_GOLANG,
    LAMBDA_RUNTIME_JAVA8,
    LAMBDA_RUNTIME_JAVA8_AL2,
    LAMBDA_RUNTIME_JAVA11,
    LAMBDA_RUNTIME_NODEJS12X,
    LAMBDA_RUNTIME_NODEJS14X,
    LAMBDA_RUNTIME_PROVIDED,
    LAMBDA_RUNTIME_PROVIDED_AL2,
    LAMBDA_RUNTIME_PYTHON36,
    LAMBDA_RUNTIME_PYTHON37,
    LAMBDA_RUNTIME_PYTHON38,
    LAMBDA_RUNTIME_PYTHON39,
    LAMBDA_RUNTIME_RUBY27,
)
from localstack.services.install import (
    GO_RUNTIME_VERSION,
    INSTALL_PATH_LOCALSTACK_FAT_JAR,
    TEST_LAMBDA_JAVA,
    download_and_extract,
)
from localstack.utils import testutil
from localstack.utils.aws import aws_stack
from localstack.utils.common import (
    cp_r,
    get_arch,
    get_os,
    load_file,
    mkdir,
    new_tmp_dir,
    retry,