added some oauth2 client options

modules/features/forgejo.nix

@@ -64,6 +64,13 @@
                   CERT_FILE = config.mtls.certFile;
                 })
               ];
+              oauth2_client = {
+                ENABLE_AUTO_REGISTRATION = true;
+                USERNAME = "nickname";
+                UPDATE_AVATAR = true;
+                ACCOUNT_LINKING = "login";
+                REGISTER_EMAIL_CONFIRM = false;
+              };
               repository = {
                 ENABLE_PUSH_CREATE_USER = true;
               };