Update har_capture_reader.py

Added UTF-8 encoding to HAR capture reader

mitmproxy2swagger/har_capture_reader.py

@@ -71,7 +71,7 @@ class HarCaptureReader:
         self.progress_callback = progress_callback
     def captured_requests(self) -> Iterator[HarFlowWrapper]:
         har_file_size = os.path.getsize(self.file_path)
-        with open(self.file_path, 'r') as f:
+        with open(self.file_path, 'r', encoding='utf-8') as f:
             data = json_stream.load(f)
             for entry in data['log']['entries'].persistent():
                 if self.progress_callback: