do not use ES12 yet

Author: Erwin Dondorp

tests/helpers/wait-for-docker.js

@@ -1,7 +1,7 @@
 /* global process */
 
 const url = process.env.DOCKER_URL || "http://localhost:3333/";
-const timeoutMs = 60_000;
+const timeoutMs = 60000;
 const intervalMs = 1000;
 const start = Date.now();