ci(actions): Update actions/cache v4 to v5

why: Security and feature updates
what:
- Update actions/cache from v4 to v5

refs:
- https://github.com/actions/cache/releases/tag/v5.0.0

Author: tony

.github/workflows/tests.yml

@@ -37,7 +37,7 @@ jobs:
 
       - name: Setup tmux build cache for tmux ${{ matrix.tmux-version }}
         id: tmux-build-cache
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ~/tmux-builds/tmux-${{ matrix.tmux-version }}
           key: tmux-${{ matrix.tmux-version }}