Bump actions/checkout from 3.2.0 to 3.3.0 (dart-lang/lints#98)

Bumps [actions/checkout](https://github.com/actions/checkout) from 3.2.0 to 3.3.0.
- [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/755da8c3cf115ac066823e79a1e1788f8940201b...ac593985615ec2ede58e132d2e21d2b1cbd6127c)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
diff --git a/pkgs/lints/.github/workflows/validate.yml b/pkgs/lints/.github/workflows/validate.yml
index c93dee0..b89093d 100644
--- a/pkgs/lints/.github/workflows/validate.yml
+++ b/pkgs/lints/.github/workflows/validate.yml
@@ -21,7 +21,7 @@
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@755da8c3cf115ac066823e79a1e1788f8940201b
+      - uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c
 
       - name: Check for sources
         run: |