ci: make sure release part of CI is running only on main

.github/workflows/ci.yml

@@ -41,13 +41,16 @@ jobs:
           file_pattern: 'README.md'
 
       # release
-      - name: Setup git user
+      - if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+        name: Setup git user
         run: |
           git config --global user.name "$(git --no-pager log --format=format:'%an' -n 1)"
           git config --global user.email "$(git --no-pager log --format=format:'%ae' -n 1)"
-      - name: remove git auth
+      - if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+        name: remove git auth
         run: git config --unset http.https://github.com/.extraheader
-      - name: Authenticate with Registry
+      - if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+        name: Authenticate with Registry
         run: |
           echo "registry=http://registry.npmjs.org/" >> .npmrc
           echo "//registry.npmjs.org/:_authToken=$NPM_TOKEN" >> .npmrc