Use utf-8 encoding when loading institutions

Thanks to @TheLime1 for pointing this out

blackboard_sync/institutions.py

@@ -82,8 +82,9 @@ class Institution(BaseModel):
 
 def load() -> list[Institution]:
  db = []
+ db_file = Path(__file__).parent / UNIVERSITY_DB
 
- with (Path(__file__).parent / UNIVERSITY_DB).open() as f:
+ with db_file.open(encoding='utf-8') as f:
  db = json.load(f)
 
  return [Institution(**uni) for uni in db]