[infra] Checkout code on main to detect changes (#2904)

Co-authored-by: Alan West <[email protected]>

Author: Kielek

.github/workflows/ci.yml

@@ -15,6 +15,10 @@ jobs:
     outputs:
       changes: ${{ steps.changes.outputs.changes }}
     steps:
+    - name: check out code
+      uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      if: ${{ github.event_name == 'push' }}
+
     - uses: AurorNZ/paths-filter@3b1f3abc3371cca888d8eb03dfa70bc8a9867629 # v4.0.0
       id: changes
       with: