Added support for sarif reporting

[Barroqueiro]

Hi!

Fixed the issue I created here, following the work done on your docker-bandit repository, I added support for sarif reporting within this image of ESLint.

Reporting in sarif for the current directory can be done with the following command

docker run -it --rm -v $(pwd):/data cytopia/eslint -f @microsoft/eslint-formatter-sarif <file_here > -o /data/<output_file_here>

Hope this can be integrated into the project.

Thank you!