CI: harddcode docs dest to stable0.15

until we migrate from an ubuntu based image to a fedora one

.github/workflows/docs.yml

@@ -39,7 +39,7 @@ jobs:
           command: doc
           args: -p atk -p atk-sys -p gdk -p gdk-sys -p gdkx11 -p gdkx11-sys -p gtk -p gtk3-macros -p gtk-sys --features dox --no-deps
       - run: echo "RELEASE=$(echo '${{ github.event.release.tag_name }}' | grep -Po '(\d+)\.(\d+)')" >> ${GITHUB_ENV}
-      - run: echo "DEST=$(if [ "$GITHUB_EVENT_NAME" == "release" ]; then echo 'stable/${{ env.RELEASE }}'; else echo 'git'; fi)" >> ${GITHUB_ENV}
+      - run: echo "DEST=stable/0.15" >> ${GITHUB_ENV}
       - name: Grab gtk-rs LOGO
         if: ${{ (github.event_name == 'push' && github.ref == 'refs/heads/master') || github.event_name == 'release' }}
         run: |