Add phone number validator using regex

Author: Shashank-511

strings/phone_number_validator.py

@@ -0,0 +1,15 @@
+import re
+def validate_phone_number(phone: str) -> bool:
+    """
+    Validates a 10-digit Indian phone number.
+    >>> validate_phone_number("9876543210")
+    True
+    >>> validate_phone_number("1234567890")
+    False
+    >>> validate_phone_number("abcd123456")
+    False
+    >>> validate_phone_number("abcdedad")
+    False
+    """
+    pattern = r'^[6-9]\d{9}$'
+    return re.fullmatch(pattern, phone) is not None