Update actions/checkout action to v7

Author: renovate[bot]

.github/workflows/balena.yml

@@ -14,7 +14,7 @@ jobs:
     strategy:
       fail-fast: true
     steps:
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
       - uses: balena-io/deploy-to-balena-action@63a685c4b9c898c38e66776284a78c4e50ec8c97 # v2.0.136
         with:
           balena_token: ${{ secrets.BALENA_TOKEN }}