Security release

Updates to dependencies, including switching to use elm-tooling in development.

Minor Fixes and Updates

• Add missing working-directory to action.yml
• Add missing required properties to action.yml
• Update project dependencies

Working Directory Option

Adds a working-directory option incase your Elm project is not in the current directory.

Security Release

• Bumps lodash from 4.17.15 to 4.17.19. (#13)

First Release

• error annotations for any files that are not formatted
• support for multiple files to elm-format
• support for file globs
• support for excluding files (via globs)