[firebase-release] Removed change log and reset repo after 3.4.0 release

Author: google-oss-bot

CHANGELOG.md

@@ -1,4 +0,0 @@
-**IMPORTANT: Please update to this version of `firebase-functions` if you are using Node.js 10 functions, otherwise your functions will break in production.**
-
-- Prevents deployment and runtime issues caused by upcoming changes to Cloud Functions infrastructure for Node.js 10 functions. (Issue #630)
-- Adds support for writing scheduled functions under handler namespace.