Bump actions/checkout from 2 to 4 in /examples

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...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>

examples/basic.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 15
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - uses: shimataro/ssh-key-action@v2
       with:
         key: ${{ secrets.TRELLIS_DEPLOY_SSH_PRIVATE_KEY }}

examples/multi-repo.yml

@@ -17,15 +17,15 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
       with:
         path: site
     - uses: actions/setup-node@v4
       with:
         node-version: '16'
         cache: yarn
         cache-dependency-path: site/web/app/themes/sage/yarn.lock
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
       with:
         repository: example/example.com
         path: trellis

examples/sage.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - uses: actions/setup-node@v4
       with:
         node-version: '16'