Dockerfile: Install taskcluster python library. (#1470)
Dockerfile: Install taskcluster python library. (#1470)

ekager/focus-android,mastizada/focus-android,layely/focus-android,mozilla-mobile/focus-android,pocmo/focus-android,mozilla-mobile/focus-android,layely/focus-android,jonalmeida/focus-android,layely/focus-android,jonalmeida/focus-android,mastizada/focus-android,mastizada/focus-android,ekager/focus-android,ekager/focus-android,pocmo/focus-android,layely/focus-android,liuche/focus-android,mozilla-mobile/focus-android,mozilla-mobile/focus-android,Benestar/focus-android,ekager/focus-android,mozilla-mobile/focus-android,ekager/focus-android,jonalmeida/focus-android,mozilla-mobile/focus-android,pocmo/focus-android,pocmo/focus-android,liuche/focus-android,Benestar/focus-android,ekager/focus-android,liuche/focus-android,liuche/focus-android,pocmo/focus-android,jonalmeida/focus-android,liuche/focus-android,mastizada/focus-android,jonalmeida/focus-android,Benestar/focus-android,jonalmeida/focus-android,layely/focus-android,pocmo/focus-android,Benestar/focus-android,mastizada/focus-android,liuche/focus-android,Benestar/focus-android