fixed pipline publish branch

Author: GreyLabsDev

.github/workflows/main.yml

@@ -40,4 +40,4 @@ jobs:
       run: |
         git add build/web/ -f
         git commit -m "Deploy Flutter Web Application"
-        git push origin $(git subtree split --prefix=build/web/):main -f
+        git push origin $(git subtree split --prefix=build/web/):gh-pages -f