github/workflows: disable commit job on pr

.github/workflows/user_project_ci.yml

diff --git a/.github/workflows/user_project_ci.yml b/.github/workflows/user_project_ci.yml
index d8994d8..4840801 100644
--- a/.github/workflows/user_project_ci.yml
+++ b/.github/workflows/user_project_ci.yml
@@ -182,6 +182,7 @@
         EOF
 
   commit:
+    if: github.ref == 'main'
     needs:
     - precheck
     - gds