Add deprecation warning for dynamic_link_domain

Author: huwmartin

firebase_admin/_user_mgt.py

@@ -18,6 +18,7 @@
 from collections import defaultdict
 import json
 from urllib import parse
+import warnings
 
 import requests
 
@@ -492,6 +493,8 @@ class ActionCodeSettings:
     def __init__(self, url, handle_code_in_app=None, dynamic_link_domain=None, ios_bundle_id=None,
                  android_package_name=None, android_install_app=None, android_minimum_version=None,
                  link_domain=None):
+        if dynamic_link_domain is not None:
+            warnings.warn('dynamic_link_domain is deprecated, use link_domain instead', DeprecationWarning)
         self.url = url
         self.handle_code_in_app = handle_code_in_app
         self.dynamic_link_domain = dynamic_link_domain