[skip changelog] Use major version ref for `actions/github-script` action (#1404)

Use of the major version ref will cause the workflow to benefit from ongoing development to its `actions/github-script`
GitHub Actions action dependency at each patch or minor release up until such time as a new major release is made.
Dependabot will submit a PR at that time, which will serve as the notification that a newer version is available. At that
time, the maintainer should evaluate whether any changes to the workflow are required by the breaking change that
triggered the major release before manually updating the major ref (i.e., `uses: actions/github-script@v5`).

.github/workflows/github-stats.yaml

@@ -15,7 +15,7 @@ jobs:
     steps:
       - name: Fetch downloads count
         id: fetch
-        uses: actions/github-script@v4.0.2
+        uses: actions/github-script@v4
         with:
           github-token: ${{github.token}}
           script: |