Github Actions: `Rscript -e "remotes::install_github...` fails with `Error: Failed to install 'unknown package' from GitHub:` : `cannot open URL '`

I have a workflow file which was running fine every time, but some time on August 5/6th (this ran on both days, and has been failing since August 6th). I assume an update was pushed to something, as the Rscript -e "remotes::install_github(' lines fails with:

Error: Error: Failed to install ‘unknown package’ from GitHub:
cannot open URL

for an example of this failure, see run

I tried swapping the two Rscript -e "remotes::install_github( lines around, and it still fails with the same error, which makes me think it’s not related to the packages themselves, and rather something else in this command.

Workflow file for reference:

name: Show last tweet

    branches: [ master ]
    - cron:  '0 0 * * *'
    runs-on: macos-latest
      - uses: actions/checkout@v2
      - uses: r-lib/actions/setup-r@v1
      - name: Install Package Dependencies
        run: |-
          Rscript -e "install.packages('remotes')"
          Rscript -e "remotes::install_github('rstudio/webshot2')"
          Rscript -e "remotes::install_github('gadenbuie/tweetrmd')"
          Rscript -e "install.packages('rtweet')"
      - name: Run script
          ACCESS_SECRET: ${{ secrets.ACCESS_SECRET }}
          ACCESS_TOKEN: ${{ secrets.ACCESS_TOKEN }}
          CONSUMER_KEY: ${{ secrets.CONSUMER_KEY }}
          CONSUMER_SECRET: ${{ secrets.CONSUMER_SECRET }}
        run: |-
          Rscript -e "source('script.R')"
      - name: Commit results
        uses: stefanzweifel/git-auto-commit-action@v4.4.0
          branch: master
          commit_message: "Update the latest tweet"