Bump actions/cache from 5 to 6 (#286)

Bumps [actions/cache](https://github.com/actions/cache) from 5 to 6.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v5...v6)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -49,7 +49,7 @@ jobs:
       - id: cache-key-generator
         run: echo "key=composer-${{ runner.os }}-${{ hashFiles('composer.lock') }}" >> $GITHUB_OUTPUT
 
-      - uses: actions/cache@v5
+      - uses: actions/cache@v6
         with:
           path: |
             vendor
@@ -85,7 +85,7 @@ jobs:
       image: ghcr.io/spomky-labs/phpqa:8.4
     steps:
       - uses: actions/checkout@v7.0.0
-      - uses: actions/cache@v5
+      - uses: actions/cache@v6
         with:
           path: |
             vendor
@@ -101,7 +101,7 @@ jobs:
       image: ghcr.io/spomky-labs/phpqa:8.4
     steps:
       - uses: actions/checkout@v7.0.0
-      - uses: actions/cache@v5
+      - uses: actions/cache@v6
         with:
           path: |
             vendor
@@ -117,7 +117,7 @@ jobs:
       image: ghcr.io/spomky-labs/phpqa:8.4
     steps:
       - uses: actions/checkout@v7.0.0
-      - uses: actions/cache@v5
+      - uses: actions/cache@v6
         with:
           path: |
             vendor
@@ -156,7 +156,7 @@ jobs:
       image: ghcr.io/spomky-labs/phpqa:8.4
     steps:
       - uses: actions/checkout@v7.0.0
-      - uses: actions/cache@v5
+      - uses: actions/cache@v6
         with:
           path: |
             vendor