fix: incorrect usage of lock file

Author: william-silversmith

mapbuffer/mapbuffer.py

@@ -62,7 +62,7 @@ def __init__(
     self._compress = None
     self._lock = None
     if self.index_cache is not None:
-      self._lock = fasteners.InterProcessReaderWriterLock(self.index_cache)
+      self._lock = fasteners.InterProcessReaderWriterLock(f"{self.index_cache}.lock")
 
     if isinstance(data, dict):
       self.buffer = self.dict2buf(data, compress)