fix python for linkchecker

Author: mmcky

.github/workflows/linkcheck.yml

@@ -13,7 +13,7 @@ jobs:
       fail-fast: false
       matrix:
         os: ["ubuntu-latest"]
-        python-version: ["3.11"]
+        python-version: ["3.12"]
     steps:
       - name: Checkout
         uses: actions/checkout@v4