GitHub Actions to tag a repo at the beginning of each week. See blog.aspect.dev

weekly-tag.yaml

# Apply a tag to HEAD at the beginning of each week.
# We can use this to create semver-looking tags for releases like
# 2020.44.123+abc1234
on:
  schedule:
    # Mondays at 5am UTC / midnight EST
    - cron: '0 5 * * 1'

jobs:
  tagger:
    runs-on: ubuntu-latest
    steps:
      - name: tag HEAD with date +%G.%V
        run: |
          curl --request POST \
            --url https://api.github.com/repos/${{ github.repository }}/git/refs \
            --header 'authorization: Bearer ${{ secrets.GITHUB_TOKEN }}' \
            --data @- << EOF
          {
            "ref": "refs/tags/$(date +%G.%V)",
            "sha": "${{ github.sha }}"
          }
          EOF

Should the date format maybe be %G.%V, so both the year and week components will indicate the ISO week? Otherwise you could get non-monotonic tags around the start of the year:

$ for d in 2022-12-31 2023-01-01 2023-01-02; do date -d $d +'%F  %Y.%V  %G.%V'; done
2022-12-31  2022.52  2022.52
2023-01-01  2023.52  2022.52
2023-01-02  2023.01  2023.01

Ha, given that it's the second week of January I'm guessing that's not a theoretical question - thanks!

FWIW, in a repo I'm using this GH Actions recipe on, I didn't see a bug this year when it produced tags. Maybe the LC_LOCALE is different from yours or something.