V2.2 is complaining about the google oauth Json file

[kishoreyellamraju]

All the versions till 2.1 are working fine but the oauth2_proxy v2.2 is throwing the below error, does it expect the json file in a different format?

2018/08/23 15:50:27 google.go:177: can't load Google credentials file:google: read JWT from JSON credentials: 'type' field is "" (expected "service_account")