ci: don't fetch develop when running on develop

Author: UdjinM6

.github/workflows/build-src.yml

@@ -34,7 +34,9 @@ jobs:
         id: setup
         run: |
           git config --global --add safe.directory "$PWD"
-          git fetch origin develop:develop
+          if [ ${{ github.head_ref }} != "develop" ]; then
+            git fetch origin develop:develop
+          fi
           BUILD_TARGET="${{ inputs.build-target }}"
           source ./ci/dash/matrix.sh
           echo "HOST=${HOST}" >> $GITHUB_OUTPUT