Bump actions/checkout from 5.0.0 to 6.0.0 (#334)

Bumps [actions/checkout](https://github.com/actions/checkout) from 5.0.0 to 6.0.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/08c6903cd8c0fde910a37f88322edcfb5dd907a8...1af3b93b6815bc44a9784bd300feb67ff0d1eeb3)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: 6.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 3717315..1f158c0 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -20,7 +20,7 @@
       matrix:
         sdk: [dev]
     steps:
-    - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3
     - uses: dart-lang/setup-dart@e51d8e571e22473a2ddebf0ef8a2123f0ab2c02c
       with:
         sdk: ${{ matrix.sdk }}
@@ -42,7 +42,7 @@
         os: [ubuntu-latest]
         sdk: [3.4, stable, dev]
     steps:
-    - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3
     - uses: dart-lang/setup-dart@e51d8e571e22473a2ddebf0ef8a2123f0ab2c02c
       with:
         sdk: ${{ matrix.sdk }}
@@ -68,7 +68,7 @@
         os: [ ubuntu-latest ]
         sdk: [ 3.4, stable, dev ]
     steps:
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8
+      - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3
       - uses: dart-lang/setup-dart@e51d8e571e22473a2ddebf0ef8a2123f0ab2c02c
         with:
           sdk: ${{ matrix.sdk }}