Fix linkcheck failures (#6455)

* Use scitools-ci token for link checking.

* Lychee ignore Stackoverflow.

Author: trexfeathers

.github/workflows/ci-linkchecks.yml

@@ -13,10 +13,18 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: "Generate token"
+        uses: actions/create-github-app-token@v2
+        id: generate-token
+        with:
+          app-id: ${{ secrets.AUTH_APP_ID }}
+          private-key: ${{ secrets.AUTH_APP_PRIVATE_KEY }}
+
       - name: Link Checker
         id: lychee
         uses: lycheeverse/lychee-action@1d97d84f0bc547f7b25f4c2170d87d810dc2fb2c
         with:
+          token: ${{ steps.generate-token.outputs.token }}
           fail: false
           args: "--verbose './docs/**/*.rst' './docs/**/*.inc' './lib/**/*.py'"
 

.lycheeignore

@@ -32,6 +32,9 @@ https://github.com/your-user-name/iris
 # problem with bad certificate (review sometime?)
 https://scitools.github.com/cartopy
 
+# returns 403 when accessed from GitHub Actions
+https://stackoverflow.com
+
 # legacy ref in whatsnew/3.0.rst
 https://stickler-ci.com