Fix typo in URL for getting user's followers

lib/friendica_client/friendica_client.dart

@@ -537,7 +537,7 @@ class RelationshipsClient extends FriendicaClient {
     final myId = profile.userId;
     final baseUrl = 'https://$serverName/api/v1/accounts/$myId';
     final result1 = await _getApiListRequest(
-      Uri.parse('$baseUrl/followers&${page.toQueryParameters()}'),
+      Uri.parse('$baseUrl/followers?${page.toQueryParameters()}'),
     );
 
     _networkStatusService.finishConnectionUpdateStatus();