v20.0.0

[MAJOR] The worker-manager service's google provider type now requires that worker pool definitions contain an array of possible variations of workers for the pool, in the launchConfig property.
See google provider type for more detail.
Note that this is a breaking change that will cause all google-based worker pools to stop provisioning until they have been updated to the new format.
To update, change the config field by moving all fields except minCapacity and maxCapacity into an array in launchConfigs:

some/worker:
  config:
    minCapacity: 25
    maxCapacity: 50
-   region: us-central1
-   zone: us-central1-a
-   capacityPerInstance: 1
-   minCpuPlatform: "Intel Skylake"
-   ...
+   launchConfigs:
+     - region: us-central1
+       zone: us-central1-a
+       capacityPerInstance: 1
+       minCpuPlatform: "Intel Skylake"
+       ...

(bug 1585102) The GitHub service now posts a more useful comment to pull requests and commits when an InsufficientScopes error occurs.
The message now includes the scopes used to make the API call, including the assume:repo:.. role.