explicitly fetch the base branch

Author: pablo-guardiola

.github/workflows/android.yaml

@@ -21,6 +21,11 @@ jobs:
         with:
           fetch-depth: 0
 
+      # Explicitly fetch the base branch
+      - name: Fetch base branch
+        run: |
+          git fetch origin $GITHUB_BASE_REF
+
       - name: check for relevant changes
         id: check_changes
         run: |