Add keepalive using GitHub actions API

[gautamkrishnar]

Now GitHub supports re-enabling the workflows using GitHub API.

gh api -X PUT repos/{ repo }/actions/workflows/{ actionFile }/enable

ToDo

• Provide API for action developers to use this approach
• Add this as an option to the keepalive workflow

ref: #1

[gautamkrishnar]

@all-contributors please add @liskin for ideas

[allcontributors]

@gautamkrishnar

I've put up a pull request to add @liskin! 🎉