only push to gh-pages branch on commits to master

.github/workflows/vm-build.yml

@@ -137,15 +137,29 @@ jobs:
       - run: npm run benchmarks -- 10 | tee output.txt
         working-directory: ${{ env.cwd }}
 
-      - name: Store benchmark result
+      - name: Set auto-push for benchmarks to true if on master
+        id: auto_push
+        run: |
+          if [$REF == 'refs/heads/master']
+          then
+              echo "::set-output name=auto_push::true"
+          else
+              echo "::set-output name=auto_push::false"
+          fi
+        env:
+          REF: ${{ github.ref }}
+
+      - name: Compare benchmarks
         uses: rhysd/github-action-benchmark@v1
         with:
           tool: 'benchmarkjs'
           # Where the output from the benchmark tool is stored
           output-file-path: ${{ env.cwd }}/output.txt
-          # GitHub API token to make a commit comment
-          github-token: ${{ secrets.GITHUB_TOKEN }}
           # Enable alert commit comment
           comment-on-alert: true
-          # Push and deploy GitHub pages branch automatically
-          auto-push: true
+          # Always leave a commit comment comparing the current benchmark with previous
+          comment-always: true
+          # GitHub API token to make a commit comment
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          # Push and deploy to GitHub pages branch automatically (if on master)
+          auto-push: ${{ steps.auto_push.outputs.auto_push }}