Bump actions/cache from 4 to 5 (#1062)

Author: dependabot[bot]

.github/workflows/ci.yaml

@@ -33,7 +33,7 @@ jobs:
         with:
           go-version: ${{ matrix.go-version.version }}
       - name: Cache
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ~/go/pkg/mod
           key: ${{ runner.os }}-conformance-ci-${{ hashFiles('**/go.sum') }}