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](actions/checkout@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/hassfest.yaml

@@ -10,6 +10,6 @@ jobs:
   validate:
     runs-on: "ubuntu-latest"
     steps:
-      - uses: "actions/checkout@v3"
+      - uses: "actions/checkout@v4"
       - uses: home-assistant/actions/hassfest@master
 

.github/workflows/validate.yml

@@ -10,7 +10,7 @@ jobs:
   validate:
     runs-on: "ubuntu-latest"
     steps:
-      - uses: "actions/checkout@v3"
+      - uses: "actions/checkout@v4"
       - name: HACS validation
         uses: "hacs/action@main"
         with: