Feature request: DockerHub image

### Describe your idea/feature/enhancement

I wish SAM CLI would be present as Docker image on Docker Hub.

### Proposal

I want to be faster than now. Installation process coul be long or every time I want the last version I cannot spend too much time.
With tags, I can stay to a stable version and update when I need or test every time with "latest" version.

Things to consider:
1. aws-cli already present https://hub.docker.com/r/amazon/aws-cli
```
docker run --rm -it -v /var/run/docker.sock:/var/run/docker.sock --entrypoint /bin/bash amazon/aws-cli
```
2. similar project is Maven https://hub.docker.com/_/maven
```
docker run -it --rm -v "$PWD":/usr/src/mymaven -v "$HOME/.m2":/root/.m2 -v /var/run/docker.sock:/var/run/docker.sock -w /usr/src/mymaven maven mvn clean install
```

### Additional Details