checks out the PR head sha for linting

.github/workflows/linting.yaml

@@ -48,8 +48,13 @@ jobs:
         site: ['platform', 'upsun']
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
-
+        uses: actions/checkout@v4
+        with:
+          # we need to checkout the PR repo/branch even if it's a fork because the action in the next step needs to
+          # check the markdown from the PR itself. Plus, we're only running this job if a PR from fork has been approved
+          fetch-depth: 0
+          ref: ${{ github.event.pull_request.head.sha }}
+      - uses: ./.github/actions/redirection-verification
       - name: Vale
         uses: errata-ai/vale-action@reviewdog
         with: