Bump actions/checkout from 2 to 3 (#176)

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 3.
- [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/v2...v3)

---
updated-dependencies:
- dependency-name: actions/checkout
  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/build.yaml b/.github/workflows/build.yaml
index 09537e6..c095a0f 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -17,7 +17,7 @@
       image:  google/dart:dev
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - run: dart pub get
       - run: dart format --output=none --set-exit-if-changed .
       - run: dart analyze --fatal-infos