CI: upgrade actions/cache to v5

Author: kleisauke

.github/workflows/ci.yml

@@ -26,7 +26,7 @@ jobs:
             key=${{ hashFiles('lib/**', 'src/**', 'build.sh', 'Dockerfile') }}
           fi
           echo "key=$key" >> $GITHUB_OUTPUT
-      - uses: actions/cache@v4
+      - uses: actions/cache@v5
         id: cache
         with:
           path: |
@@ -56,7 +56,7 @@ jobs:
       - uses: actions/setup-node@v6
         with:
           node-version: ${{ matrix.nodejs_version }}
-      - uses: actions/cache/restore@v4
+      - uses: actions/cache/restore@v5
         with:
           path: |
             lib
@@ -84,7 +84,7 @@ jobs:
       - uses: actions/setup-node@v6
         with:
           node-version: 24
-      - uses: actions/cache/restore@v4
+      - uses: actions/cache/restore@v5
         with:
           path: |
             lib