ATEAM-10574 update docs for local testing

[cmckeen]

Please read CONTRIBUTING.md for details on our code of conduct, and the process for submitting pull requests to us.

Fixes #99

Proposed Changes

• Added a new Goreleaser yaml that only builds the image locally without attempting to publish to Dockerhub
• Created a separate Drone pipeline that can be when running drone locally

Description

• Did the above, and added relevant entries to the changelog and CONTRIBUTING.MD

Checklist

• [x] Read the CONTRIBUTING document.
• [x] Read the CODE OF CONDUCT document.
• [x] Add tests to cover changes.
• [x] Ensure your code follows the code style of this project.
• [x] Ensure CI and all other PR checks are green OR
  • [x] Code compiles correctly.
  • [x] Created tests which fail without the change (if possible).
  • [x] All new and existing tests passed.
• [x] Add your changes to Unreleased section of CHANGELOG.
• [x] Improve and update the README (if necessary).
• [x] Ensure documentation is up-to-date. The same file will be updated in plugin index when your PR is accepted, so it will be available for end-users at http://plugins.drone.io.