github: revert back to running git fetch --tags manually

checkout@v4 fetch-tags: true does not seem to work as expected
[1]. Version matrix ends up missing the tag for stable:

matrix={"include":[{"ref":"master","name":"dev"},{"ref":"","name":"stable"}]}

Work around this by reverting back to running git fetch --tags manually.

[1] actions/checkout#1781

.github/workflows/docs.yml

@@ -13,8 +13,8 @@ jobs:
       matrix: ${{ steps.version-matrix.outputs.matrix }}
     steps:
       - uses: actions/checkout@v4
-        with:
-          fetch-tags: true
+      - name: Fetch tags
+        run: git fetch --tags origin
       - name: Set version matrix
         id: version-matrix
         run: echo "matrix=$(./.github/config.sh)" | tee $GITHUB_OUTPUT