feat: add weekly tags

.github/workflows/tag.yml

@@ -0,0 +1,25 @@
+name: Weekly tag
+
+on:
+  schedule:
+    - cron: "0 10 * * 0"
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+steps:
+  - name: 🏷️ Create/update tag
+    uses: actions/github-script@v7
+    with:
+      script: |
+        const now = Date.now();                
+        const onejan = new Date(now.getFullYear(), 0, 1);
+        /* This is not a ISO-8601 week number but works well for versioning */
+        const week = Math.ceil((((now.getTime() - onejan.getTime()) / 86400000) + onejan.getDay() + 1) / 7);
+        github.rest.git.createRef({
+          owner: context.repo.owner,
+          repo: context.repo.repo,
+          ref: `refs/tags/v${ now.fullYear() }.${ week }`,
+          sha: context.sha
+        })