refresh keycloak tokens
example https://gitlab.cern.ch/authzsvc/docs/keycloak-tokens-test/blob/master/keycloak-tokens-test/Server.cs
check the RefreshToken method, that shows the parameters you need to use for a POST to refresh a token
example https://gitlab.cern.ch/authzsvc/docs/keycloak-tokens-test/blob/master/keycloak-tokens-test/Server.cs
check the RefreshToken method, that shows the parameters you need to use for a POST to refresh a token