ci: update actions/checkout action to v7 (#286)

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

Author: renovate[bot]

.github/workflows/ci.yml

@@ -23,7 +23,7 @@ jobs:
 
     steps:
       - name: ⏬ Checkout
-        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           fetch-depth: 0
 

.github/workflows/release-please.yml

@@ -65,7 +65,7 @@ jobs:
 
     steps:
       - name: ⏬ Checkout
-        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
 
       - name: 🔽 Setup dotnet from global.json
         uses: actions/setup-dotnet@9a946fdbd5fb07b82b2f5a4466058b876ab72bb2 # v5.3.0