Let notion loader support utf-8 and make it default.

libs/langchain/langchain/document_loaders/notion.py

@@ -8,16 +8,17 @@
 class NotionDirectoryLoader(BaseLoader):
     """Load `Notion directory` dump."""
 
-    def __init__(self, path: str):
+    def __init__(self, path: str, encoding: str = 'utf-8'):
         """Initialize with a file path."""
         self.file_path = path
+        self.encoding = encoding
 
     def load(self) -> List[Document]:
         """Load documents."""
         ps = list(Path(self.file_path).glob("**/*.md"))
         docs = []
         for p in ps:
-            with open(p) as f:
+            with open(p, encoding=self.encoding) as f:
                 text = f.read()
             metadata = {"source": str(p)}
             docs.append(Document(page_content=text, metadata=metadata))