Fixed #150 -- Fixed error when logging out.

Turns out the trac-github extension is not really maintained
at the moment and is not compatible with Trac 1.4.
The solution (temporary hopefully) is to fork it and do the minimal
necessary fixes ourselves because why not

requirements.txt

@@ -16,7 +16,10 @@ https://trac-hacks.org/browser/xmlrpcplugin/trunk?rev=18591&format=zip
 oauthlib==2.1.0
 requests==2.20.1
 requests-oauthlib==1.0.0
-trac-github==2.3
+# trac-github is unmaintained at this time and not compatible with Trac 1.4
+# See issue https://github.com/trac-hacks/trac-github/issues/136 for example
+# So obviously the solution is a fork, this one will surely never go unmaintained
+trac-github @ git+https://github.com/bmispelon/trac-github.git@trac-1.4
 
 gunicorn==19.10.0
 sentry-sdk==1.11.0