Fix docs workflow

.github/workflows/docs.yml

@@ -29,6 +29,18 @@ jobs:
       -
         name: Checkout
         uses: actions/checkout@v2
+      - name: Prepare
+        id: prepare
+        run: |
+          VERSION=edge
+          RELEASE=false
+          if [[ $GITHUB_REF == refs/tags/* ]]; then
+            VERSION=${GITHUB_REF#refs/tags/v}
+          fi
+          if [[ $VERSION =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then
+            RELEASE=true
+          fi
+          echo ::set-output name=release::${RELEASE}
       -
         name: Build mkdocs Docker image
         run: |
@@ -40,7 +52,7 @@ jobs:
           sudo chown -R $(id -u):$(id -g) ./site
       -
         name: Deploy
-        if: success() && github.event_name != 'pull_request' && (endsWith(github.ref, github.event.repository.default_branch) || startsWith(github.ref, 'refs/tags/'))
+        if: success() && github.event_name != 'pull_request' && (endsWith(github.ref, github.event.repository.default_branch) || steps.prepare.outputs.release == 'true')
         uses: crazy-max/ghaction-github-pages@v2
         with:
           target_branch: gh-pages