Use utf-8 in find missing locale script (LAION-AI#1891)

Windows don't use utf-8 locale, so running this script fails. Setting
the encoding in open fixes that.

Co-authored-by: Lukáš Frolka <denzil@lunaen.com>

Author: d3nzil

scripts/frontend-development/find-missing-locales.py

@@ -36,8 +36,8 @@ def print_result(missing, not_translated, file):
 
 
 def audit(file, en_file):
-    en_json = load(open(en_file))
-    translation_json = load(open(file))
+    en_json = load(open(en_file, encoding="utf-8"))
+    translation_json = load(open(file, encoding="utf-8"))
     return (get_missing(en_json, translation_json), get_not_translated(en_json, translation_json), file)