ci(git-artifacts): ensure that node.js is available

The 'Generate bundle artifacts' step implicitly calls
`add-release-note.js`, which required node.js.

However, on our self-hosted Windows/ARM64 runners (the general
availability of GitHub's hosted runners cannot come soon enough!), we do
not install node.js. So let's use a dedicated GitHub Action to ensure
that it's there when it is needed most.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

.github/workflows/git-artifacts.yml

@@ -56,7 +56,10 @@ jobs:
 
           mkdir -p build-installers/usr/src &&
           mv build-extra build-installers/usr/src/
-
+      - uses: actions/setup-node@v4
+        # needed to run `add-release-note.js` (via `./please.sh mention feature`)
+        with:
+          node-version: 22.x
       - name: Generate bundle artifacts
         shell: bash
         run: |