[godot] Fix convert.py to release lock before renaming .json files.

spine-godot/convert.py

@@ -21,8 +21,10 @@ import pathlib
 import codecs
 
 def convert_json(filename):
-    with open(filename) as file:
+    file = codecs.open(filename, "r", "utf-8")
     content = file.read()
+    file.close()
+    
     if "skeleton" in content and "hash" in content and "spine" in content:
         path = pathlib.Path(filename)
         new_path = path.with_suffix('.spine-json')