chore: repair workflow file

Author: fabianbormann

.github/workflows/publish.yaml

@@ -10,8 +10,7 @@ on:
 jobs:
   plot-and-publish:
     runs-on: ubuntu-latest
-    if: |
-      "contains(github.event.head_commit.message, 'release-please--branches--main')"
+    if:  "contains(github.event.head_commit.message, 'release-please--branches--main')"
     steps:
       - name: ⬇️ Checkout repository
         uses: actions/checkout@v3