docs(svn auth): Fix link

Author: tony

libvcs/cmd/svn.py

@@ -229,7 +229,7 @@ def auth(
     ):
         """
         Wraps `svn auth
-        <https://svnbook.red-bean.com/en/1.7/svn.ref.svn.c.auth.html>`_.
+        <https://subversion.apache.org/faq.html#plaintext-passwords>`_.
 
         Parameters
         ----------