sources/oauth: Updating token url to new google url (#1397)

the present url goes to a 404
google openid (https://accounts.google.com/.well-known/openid-configuration) says the new url is `https://oauth2.googleapis.com/token`

not using the new url makes authentik fallback on the default auth flow

authentik/sources/oauth/types/google.py

@@ -38,5 +38,5 @@ class GoogleType(SourceType):
     slug = "google"
 
     authorization_url = "https://accounts.google.com/o/oauth2/auth"
-    access_token_url = "https://accounts.google.com/o/oauth2/token"  # nosec
+    access_token_url = "https://oauth2.googleapis.com/token"  # nosec
     profile_url = "https://www.googleapis.com/oauth2/v1/userinfo"