AETHER-3034 Document models that should not be modified by customer

Change-Id: I58173b2d1b440fc1a2726d609f8ced2f9ff81b60
diff --git a/conf.py b/conf.py
index 42b5037..ac6a99e 100644
--- a/conf.py
+++ b/conf.py
@@ -248,6 +248,7 @@
     r'https://gerrit.opencord.org/.*',
     r'https://sas.goog/.*',
     r'https://www.fs.com/.*',
+    r'https://velero.io/.*',
 ]
 
 linkcheck_timeout = 3