workflow: fix merge conflict failing script

.gitea/workflows/update-flake.yaml

@@ -34,7 +34,7 @@ jobs:
             if [ $commits_ahead -ne 0 ]
             then
               git fetch origin
-              git merge --squash origin/main
+              git merge --squash origin/main || true # do not exit script on merge conflict
               git push --force-with-lease
 
               # solve potential merge conflict by taking flake.lock from main