Update actions/checkout action to v6.0.3 (#630)

Co-authored-by: dependencyupdates[bot] <218638057+dependencyupdates[bot]@users.noreply.github.com>

Author: dependencyupdates[bot]

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ jobs:
       fail-fast: false
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.2
+        uses: actions/checkout@v6.0.3
         with:
           fetch-depth: 0
       - name: Setup .NET SDK

.github/workflows/release.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.2
+        uses: actions/checkout@v6.0.3
         with:
           fetch-depth: 0
       - name: Setup .NET SDK