Bump actions/checkout from 3 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [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/v3...v4)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/test-quickstart.yml

@@ -24,7 +24,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Shallow checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Install zsh
         shell: bash
@@ -43,7 +43,7 @@ jobs:
       ZIGGY_UID: 1001  # let container EUID run-as GHA "runner" user to share cache, etc.
     steps:
       - name: Shallow checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Install Go
         id: setup-go