Add auto_commit input

[Gismo359]

Adds auto_commit to prevent commits when auto_fix is enabled.

This allows someone to do this:

- name: Run linters
  uses: wearerequired/lint-action@master
  with:
    auto_fix: true
    auto_commit: false
    mypy: true
    mypy_args: >
      --follow-imports=silent
      --ignore-missing-imports
      --implicit-optional
      --no-strict-optional
    autopep8: true
    autopep8_args: >
      --max-line-length 120
- name: suggester / lint
  uses: reviewdog/action-suggester@v1
  with:
    tool_name: lint

which gives you the mypy messages from lint-action but with the autopep8 changes as suggested changes via reviewdog.

Pretty much resolves #436 as it can be achieved through reviewdog.

[ocean90]

Thanks for the PR! What do you think about naming the option just commit? Or to be more explicit commitAndPush?