fix: correct import path in test_cache.py

Change `from src.gitfetch.cache` to `from gitfetch.cache` to fix
ModuleNotFoundError when running tests after `pip install -e .`

Author: 31413Hao

tests/test_cache.py

@@ -6,7 +6,7 @@
 from pathlib import Path
 from unittest.mock import patch
 
-from src.gitfetch.cache import CacheManager
+from gitfetch.cache import CacheManager
 
 
 class TestCacheManager: