try to auto-update readme for zig-0.12.0

.github/workflows/mastercheck.yml

@@ -36,3 +36,26 @@ jobs:
         run: zig build test-authentication
       - name: Report end of tests
         run: echo "tests finished"
+
+  update-readme:
+    runs-on: ubuntu-latest
+    permissions: 
+      id-token: write
+      contents: write
+
+    steps:
+    - name: Run script to update README
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        TAG_NAME: ${{ steps.tag.outputs.version }}
+      run: |
+        tools/announceybot.exe update-readme "zig-0.12.0"
+
+    - name: Commit and push if it has changed
+      run: |
+        git diff
+        git checkout zig-0.12.0
+        git config --local user.email "action@github.com"
+        git config --local user.name "GitHub Action"
+        git commit -am "Update README"
+        git push origin master