Bump actions/cache from 4 to 5 (#254)

Bumps [actions/cache](https://github.com/actions/cache) from 4 to 5.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v4...v5)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/test-agp-variants.yml

@@ -23,7 +23,7 @@ jobs:
         uses: actions/checkout@v6
 
       - name: Cache Gradle
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: |
             ~/.gradle/caches

.github/workflows/test-plugin.yml

@@ -17,7 +17,7 @@ jobs:
         uses: actions/checkout@v6
 
       - name: Cache Gradle
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: |
             ~/.gradle/caches
@@ -47,7 +47,7 @@ jobs:
         uses: actions/checkout@v6
 
       - name: Cache Gradle
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: |
             ~/.gradle/caches