Fix the email validation problem for a.b@c.club. (#94)

Co-authored-by: yyzhang <yuanyuan.zhang@haochezhu.club>

api/libs/helper.py

@@ -21,7 +21,7 @@ class TimestampField(fields.Raw):
 
 def email(email):
     # Define a regex pattern for email addresses
-    pattern = r"^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$"
+    pattern = r"^[\w\.-]+@([\w-]+\.)+[\w-]{2,4}$"
     # Check if the email matches the pattern
     if re.match(pattern, email) is not None:
         return email