Update actions/cache to v6

Signed-off-by: Liviu-Mihail Concioiu <liviu.concioiu@gmail.com>

Author: liviuconcioiu

.github/workflows/build.yml

@@ -59,7 +59,7 @@ jobs:
               working-directory: phpmyadmin
               run: git restore-mtime
             - name: Cache output for "${{ matrix.languageCode }}"
-              uses: actions/cache@v5
+              uses: actions/cache@v6
               with:
                 path: output/${{ matrix.languageCode }}
                 key: docs-output-${{ matrix.languageCode }}