Support GitHub PR webhooks

Story: 2000774

Change-Id: I2713c5d19326213539689e9d822831a393b2bf19
Co-Authored-By: Wayne Warren <waynr+launchpad@sdf.org>
Co-Authored-By: Jan Hruban <jan.hruban@gooddata.com>
Co-Authored-By: Jesse Keating <omgjlk@us.ibm.com>
diff --git a/requirements.txt b/requirements.txt
index 974b77f..44cef95 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,6 @@
 pbr>=1.1.0
 
+Github3.py
 PyYAML>=3.1.0
 Paste
 WebOb>=1.2.3