[@caesarxuchao](https://github.com/caesarxuchao))

* Using kubectl gcp auth plugin with a Google Service Account to authenticate to a cluster now additionally requests a token with the  "userinfo.email" scope. This way, users can write ClusterRoleBindings/RoleBindings with the email address of the service account directly. (This is a breaking change if the numeric uniqueIDs of the Google service accounts were being used in RBAC role bindings. The behavior can be overridden by explicitly...

- When configuring a JWT authenticator:
  
  If `username.expression` used 'claims.email', then 'claims.email_verified' must have been used in `username.expression` or `extra[*].valueExpression` or `claimValidationRules[*].expression`. An example claim validation rule expression that matches the validation automatically applied when `username.claim` is set to 'email' is 'claims.?email_verified.orValue(true)'.