Remove deprecated GH Action from docs

[andrewbanchich]

The Action Outputs section of the README gives @actions/upload-release-asset GitHub Action as an example of what to use for uploading an asset to upload_url. However, that Action is deprecated:

Please note: This repository is currently unmaintained by a team of developers at GitHub. The repository is here and you can use it as an example, or in Actions. However please be aware that we are not going to be updating issues or pull requests on this repository.

Furthermore, I've found that upload-release-asset isn't great for use with release-drafter because it doesn't support overwriting existing assets.

A simple and officially supported alternative would be:

run: |
  gh release upload --clobber ${{ env.VERSION }} ${{ env.FILES }}
env:
  GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
  VERSION: ${{ needs.draft_release.outputs.tag_name }}
  FILES: foo.txt baz.txt

[guilhermeblanco]

I'd argue this support should be native to this action, since a release can contain assets even on a draft state.

One place where this module contributors can get inspirarion for asset uploading is looking at what https://github.com/softprops/action-gh-release does (more specifically, here: https://github.com/softprops/action-gh-release/blob/master/src/main.ts#L63).

[jetersen]

PRs are welcome :)

[jetersen]

I will look into adding this in v6 #1204