Update HTTP2 libraries used by the Android app to be compatible with Nginx 1.13.6+

Problem Definition

Nginx 1.13.6 and newer broke compatibility with old HTTP2 libraries used by the Hipchat Android app.
More details can be found in Android app on Android 5+ cannot connect to Hipchat Data Center

Suggested Solution

Update the HTTP2 libraries to support Nginx 1.13.6 and newer

Workaround

Downgrade Nginx at your reverse proxy/load balancer to 1.13.5 or older