Use encoding="utf-8" in open. (#773)

Author: ChiahungTai

setup.py

@@ -9,7 +9,7 @@
 
 def read(rel_path: str) -> str:
     here = os.path.abspath(os.path.dirname(__file__))
-    with open(os.path.join(here, rel_path)) as fp:
+    with open(os.path.join(here, rel_path), encoding="utf-8") as fp:
         return fp.read()