Feature: Mark pull requests stale after 21 days of inactivity

[CarbonNeuron]

Pull Request

Description

I've adapted the workflow for stale issues to also include handling stale pull requests after 21 days.

Related Issue(s)

Closes #20

Changes Made

Updated mark-stale-issues.yml to also include marking stale pull requests.

• added the following lines to mark-stale-issues.yml:

  days-before-pr-stale: 21
  stale-pr-label: 'stale'
  stale-pr-message: 'This pull request has been automatically marked as stale because it has not had activity within 21 days. Thank you for your contributions.'

Checklist

• [x] I have reviewed the Contributing Guidelines for this repository.
• [x] I have followed the coding style and conventions of this project.
• [x] I have added/updated relevant documentation (if necessary).
• [x] The code is tested and all tests pass.
• [x] I have updated the version (if applicable).
• [x] All commit messages are meaningful and follow the established convention.

Additional Notes

I thought it might be simpler to leave the file called mark-stale-issues.yml but I could see how this can cause some confusion. I think renaming the file to mark-stale.yml might be better, and renaming the workflow name to Mark Stale as well. Let me know if you'd like me to do this.

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By submitting this pull request, I confirm that my contribution is made under the terms of the LICENSE for this project.

[CarbonNeuron]

@rcallaby Done! Didn't know that you wanted them in separate files, was trying to optimize action runs. I've reverted the previous change, and made a new commit that adds that new file.

[CarbonNeuron]

@rcallaby Could you please add the hacktoberfest-accepted label to this issue, or opt in on the repo? Otherwise this PR won't count.