refactor(nodejs): move build cop to flakybot (#502)

This PR was generated using Autosynth. 🌈

Synth log will be available here:
https://source.cloud.google.com/results/invocations/541df317-e090-4c6d-88b9-3f79f53b8d13/targets

- [ ] To automatically regenerate this PR, check this box.

Source-Link: googleapis/synthtool@57c23fa

packages/google-cloud-tasks/synth.metadata

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/nodejs-tasks.git",
-        "sha": "ed67466c6b1646736aea27b1144e1145471bd676"
+        "sha": "b594ebf0e52e7bc79b95e1dfeac34bfe8fe9713e"
       }
     },
     {
@@ -19,7 +19,7 @@
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "363fe305e9ce34a6cd53951c6ee5f997094b54ee"
+        "sha": "57c23fa5705499a4181095ced81f0ee0933b64f6"
       }
     }
   ],