Create official Docker image of CLI jar

[matthewadams]

Please create an official Docker image so that the CLI can be used without having to download the CLI jar from the releases page (and, to a lesser extent, so that it can be used without having java installed).

[aegixx]

Not official, but I pushed out a very basic one @ https://github.com/google/google-java-format/pull/303

[aegixx]

@matthewadams As a not-that-simple one-liner too, I'm using this:

docker run -it --rm -v $(PWD):/src openjdk:alpine sh -c "wget https://github.com/google/google-java-format/releases/download/google-java-format-1.6/google-java-format-1.6-all-deps.jar && find /src -name '*.java' | xargs java -jar google-java-format-1.6-all-deps.jar -i"

[vandmo]

Feel free to copy stuff from https://github.com/vandmo/google-java-format It has GitHub workflow for publishing to arm64 and amd64 which can easily be extended to more platforms.