test: download flakybot from github (GoogleCloudPlatform#2388)

Author: JustinBeckwith

.github/workflows/healthcare-datasets.yaml

@@ -40,5 +40,5 @@ jobs:
  - run: echo ${{github.event.action}}
  - if: ${{ github.event_name == 'schedule'}}
  run: |
- gsutil cp gs://cloud-devrel-kokoro-resources/trampoline/linux_amd64/flakybot .
+ curl https://github.com/googleapis/repo-automation-bots/releases/download/flakybot-1.1.0/flakybot -o flakybot -s
  ./flakybot