ci: fix build-docs.yaml

Author: chgl

.github/workflows/build-docs.yaml

@@ -20,7 +20,7 @@ jobs:
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
-          persist-credentials: false
+          persist-credentials: true # required for pushing to gh-pages
       - uses: actions/setup-python@42375524e23c412d93fb67b49958b491fce71c38 # v5.4.0
         with:
           python-version: "3.13"