chore(actions): update git config for forks

tools/actions/composites/update-snapshots-desktop/action.yml

@@ -38,6 +38,7 @@ runs:
     - name: Commit snapshots
       if: steps.status.outputs.status != 0 || steps.status-windows.outputs.status != 0
       run: |
+        git config --global branch.autoSetupMerge simple
         git add ./apps/ledger-live-desktop/tests/specs &&
         git commit -m "test(lld): update screenshots (${{ inputs.os }}) ${{ steps.changes.outputs.changes }} lld, test, screenshot" &&
         git restore . &&