Fixing python-version for ci-docs.

Author: shz9

.github/workflows/ci-docs.yml

@@ -20,7 +20,7 @@ jobs:
 
       - uses: actions/setup-python@v5
         with:
-          python-version: 3.x
+          python-version: 3.12
 
       - run: echo "cache_id=$(date --utc '+%V')" >> $GITHUB_ENV