Renovate Update actions/cache action to v4 (#26)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

.github/workflows/test.yml

@@ -19,7 +19,7 @@ jobs:
           go-version: '1.22'
 
       - name: Cache modules
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ~/go/pkg/mod
           key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}