Liene Jansone

There is an issue with authentification using [Issuer & Validator ](https://docs.developers.optimizely.com/full-stack/docs/authorization#issuer--validator) scheme since version 2.0.0 Issue description: `oauth/token` endpoint is expecting `Content-Type: application/json` [here](https://github.com/optimizely/agent/blob/master/pkg/routers/api.go#L155), but `auth` service is expecting `Content-Type:...