Bump actions/checkout from 3.3.0 to 3.5.0 (dart-lang/markdown#529)

Bumps [actions/checkout](https://github.com/actions/checkout) from 3.3.0 to 3.5.0.
- [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/ac593985615ec2ede58e132d2e21d2b1cbd6127c...8f4b7f84864484a7bf31766abe9204da3cbe65b3)

---
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>

pkgs/markdown/.github/workflows/flutter_markdown.yaml

diff --git a/pkgs/markdown/.github/workflows/flutter_markdown.yaml b/pkgs/markdown/.github/workflows/flutter_markdown.yaml
index c99a548..e750c72 100644
--- a/pkgs/markdown/.github/workflows/flutter_markdown.yaml
+++ b/pkgs/markdown/.github/workflows/flutter_markdown.yaml
@@ -19,13 +19,13 @@
 
     steps:
       - name: clone dart-lang/markdown
-        uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c
+        uses: actions/checkout@8f4b7f84864484a7bf31766abe9204da3cbe65b3
         with:
           repository: dart-lang/markdown
           path: markdown
 
       - name: clone flutter/packages
-        uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c
+        uses: actions/checkout@8f4b7f84864484a7bf31766abe9204da3cbe65b3
         with:
           repository: flutter/packages
           path: flutter_packages

pkgs/markdown/.github/workflows/test-package.yml

diff --git a/pkgs/markdown/.github/workflows/test-package.yml b/pkgs/markdown/.github/workflows/test-package.yml
index 37efe93..76eaf03 100644
--- a/pkgs/markdown/.github/workflows/test-package.yml
+++ b/pkgs/markdown/.github/workflows/test-package.yml
@@ -22,7 +22,7 @@
       matrix:
         sdk: [dev]
     steps:
-      - uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c
+      - uses: actions/checkout@8f4b7f84864484a7bf31766abe9204da3cbe65b3
       - uses: dart-lang/setup-dart@d6a63dab3335f427404425de0fbfed4686d93c4f
         with:
           sdk: ${{ matrix.sdk }}
@@ -49,7 +49,7 @@
         os: [ubuntu-latest]
         sdk: [2.19.0, dev]
     steps:
-      - uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c
+      - uses: actions/checkout@8f4b7f84864484a7bf31766abe9204da3cbe65b3
       - uses: dart-lang/setup-dart@d6a63dab3335f427404425de0fbfed4686d93c4f
         with:
           sdk: ${{ matrix.sdk }}
@@ -64,7 +64,7 @@
     needs: test
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c
+    - uses: actions/checkout@8f4b7f84864484a7bf31766abe9204da3cbe65b3
     - uses: dart-lang/setup-dart@d6a63dab3335f427404425de0fbfed4686d93c4f
       with:
         sdk: dev