chore(deps): update actions/checkout action to v5

Author: renovate[bot]

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           persist-credentials: false
       - name: Install Nix

.github/workflows/update-flake.yml

@@ -13,7 +13,7 @@ jobs:
       pull-requests: write
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           persist-credentials: false
       - name: Install Nix