.github: fix security vuln

.github/workflows/benchmark.yml

@@ -30,7 +30,7 @@ jobs:
         run: go test -v -run '^$' -bench '(Marshal|Unmarshal)$/codeResponse' -benchmem -benchtime 3s -cpu 1 -count 6 ./json | tee bench.txt
 
       - name: Upload Benchmarks
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         with:
           name: ${{ matrix.ref }}
           path: bench.txt
@@ -49,15 +49,15 @@ jobs:
         run: go install golang.org/x/perf/cmd/benchstat@latest
 
       - name: Download Benchmark Results
-        uses: actions/download-artifact@v2
+        uses: actions/download-artifact@v4
         with:
           path: .
 
       - name: Run Benchstat
         run: benchstat ./master/bench.txt ./${{ github.sha }}/bench.txt | tee benchstat.txt
 
       - name: Upload Benchstat Results
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         with:
           name: benchstat
           path: benchstat.txt