Update actions/checkout action to v5 (#36)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/multi-arch-build.yml

@@ -101,7 +101,7 @@ jobs:
             rel_branch: openwrt-22.03
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
 
       - name: Build APK packages ${{ matrix.arch }}
         if: ${{ github.ref_name == 'main' }}