simplify workflow

.github/workflows/build.yml

@@ -1,22 +1,7 @@
-# Zola build workflow.
-
-# Prerequisites:
-# - zola writes output to public/
-# - variables below set correctly
-#
-# Setting it up:
-#   It is a general limitation of gh-actions that they cannot make the very first
-#   deploy to gh-pages.  It will seem to work, but not appear on the CDN to be
-#   online.  You need to go to settings and set the gh-pages branch, then future
-#   deploys will work.  See
-#   https://github.com/marketplace/actions/github-pages-action#%EF%B8%8F-first-deployment-with-github_token
-
 name: Build/deploy website
 
 env:
-  ZOLA_VERSION: "0.17.2"
-  MAIN_BRANCH: "main"
-  TARGET_BRANCH: "gh-pages"
+  ZOLA_VERSION: "0.19.2"
 # CNAME: "example.org"
 
 on:
@@ -44,25 +29,14 @@ jobs:
         wget -O - \
            "https://github.com/getzola/zola/releases/download/v${ZOLA_VERSION}/zola-v${ZOLA_VERSION}-x86_64-unknown-linux-gnu.tar.gz" \
         | sudo tar xzf - -C /usr/local/bin
-    - name: Generate HTML
+    - name: Build the website
       run: zola build
-    # Add CNAME, either (first one used)
-    # - file in the root
-    # - the environment variable set above
-    - name: add CNAME
-      run: |
-        if [ -f CNAME ] ; then
-            mv CNAME public/
-            echo "Copied CNAME from repository root"
-            exit 0
-        fi
-        if [ -n ${{ env.CNAME }} ] ; then
-            echo -n ${{ env.CNAME }} > public/CNAME
-            echo "Used CNAME from the action workflow file"
-        fi
+    - name: Add CNAME
+      if: github.ref == 'refs/heads/main'
+      run: echo -n ${{ env.CNAME }} > public/CNAME
     - name: Deploy to gh-pages
-      if: ${{ github.event_name == 'push' && github.ref == format('refs/heads/{0}', env.MAIN_BRANCH) }}
-      uses: peaceiris/actions-gh-pages@v3
+      if: github.ref == 'refs/heads/main'
+      uses: peaceiris/actions-gh-pages@v4
       with:
         github_token: ${{ secrets.GITHUB_TOKEN }}
         publish_dir: ./public