Add some github projects to the Zuul tenant

There are related to Zuul in some way so may be useful there.
dogpile is currently required by the -src version of the nodepool
func test job.

Change-Id: I9026a7d68986160265f1f561d377b7402d81600a

zuul/main.yaml

@@ -1600,3 +1600,15 @@
           - zuul/zuul-sphinx
           - zuul/zuul-website
           - zuul/zuul-website-media
+      github:
+        untrusted-projects:
+          # Don't load any configuration from these projects because we
+          # don't gate them, so they could wedge our config.
+          - include: []
+            projects:
+              # Sorting projects alphabetically will help merge conflicts.
+              - ansible/ansible
+              - cherrypy/cherrypy
+              - philpep/testinfra
+              - sigmavirus24/github3.py
+              - sqlalchemy/dogpile.cache