keycloak /auth page not found

with newer versions of keycloak, the `/auth` URL is no longer avaialble.

so instead of having OIDC_CLIENT_SECRETS as

{
  "web": {
    "issuer": "http://localhost:8080/auth/realms/flask-app",
    "auth_uri": "http://localhost:8080/auth/realms/flask-app/protocol/openid-connect/auth",
    "client_id": "flask-app",
    "client_secret": "XlBGtHzPOefRKjiEB9yTcQS0WBHllAcx",
    "redirect_uris": [
      "http://localhost:5000/*"
    ],
    "userinfo_uri": "http://localhost:8080/auth/realms/flask-app/protocol/openid-connect/userinfo",
    "token_uri": "http://localhost:8080/auth/realms/flask-app/protocol/openid-connect/token",
    "token_introspection_uri": "http://localhost:8080/auth/realms/flask-app/protocol/openid-connect/token/introspect"
  }
}

it should be

{
  "web": {
    "issuer": "http://localhost:8080/realms/flask-app",
    "auth_uri": "http://localhost:8080/realms/flask-app/protocol/openid-connect/auth",
    "client_id": "flask",
    "client_secret": "pww8bSrx1sYC1oLsDkWwj7P2SS6BbpiK",
    "redirect_uris": [
      "http://localhost:5000/*"
    ],
    "userinfo_uri": "http://localhost:8080/realms/flask-app/protocol/openid-connect/userinfo",
    "token_uri": "http://localhost:8080/realms/flask-app/protocol/openid-connect/token",
    "token_introspection_uri": "http://localhost:8080/realms/flask-app/protocol/openid-connect/token/introspect",
    "bearer_only": "true"
  }
}