set new gridka path by default

bb2etp.py

 from dataclasses import dataclass, field
 from typing import Any, List, Optional, Union
-import yaml
+#import yaml
 import json
 import os
 from pathlib import Path
@@ -40,7 +40,7 @@ class BeambackgroundMetadata:
     beam_energy: str = None
     qualitiy: bool = None
     global_tags: List[str] = field(default_factory=list)
-    gridka_server: str = "root://dcachexrootd-kit.gridka.de:1094"
+    gridka_server: str = "root://dcache-kit.gridka.de:1094"
 
     @property
     def expList(self) -> List[int]: