Build(deps): 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)
- [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/phpunit.yml

@@ -35,7 +35,7 @@ jobs:
           submodules: true
 
       - name: Checkout circles dependency
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           repository: nextcloud/circles
           ref: ${{ matrix.server-versions }}
@@ -127,7 +127,7 @@ jobs:
           submodules: true
 
       - name: Checkout circles dependency
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           repository: nextcloud/circles
           ref: ${{ matrix.server-versions }}
@@ -203,7 +203,7 @@ jobs:
           submodules: true
 
       - name: Checkout circles dependency
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           repository: nextcloud/circles
           ref: ${{ matrix.server-versions }}
@@ -289,7 +289,7 @@ jobs:
           submodules: true
 
       - name: Checkout circles dependency
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           repository: nextcloud/circles
           ref: ${{ matrix.server-versions }}