Add benchmark script (#666)

test/benchmark/tests/concurrency-level/sample.js

@@ -0,0 +1,10 @@
+import http from "k6/http";
+import { check } from "k6";
+
+export default function() {
+    let params = { timeout: 30 }
+    let res = http.get(`${__ENV.FN_ENDPOINT}`)
+    check(res, {
+        "status is 200": (r) => r.status === 200
+    });
+};