ci: update cache action

Author: infinitis

.github/workflows/ci.yml

@@ -57,7 +57,7 @@ jobs:
     - name: Run formatting check
       run: mix format --check-formatted
     - name: Restore Dialyzer PLT cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       id: dialyzer_plt_cache
       with:
         path: _build/dialyzer