[firebase-release] Removed change log and reset repo after 4.7.0 release

Author: google-oss-bot

CHANGELOG.md

@@ -1,4 +0,0 @@
-- Fixes access on deeply nested, nonexistent property. (#1432)
-- Add IteratedDataSnapshot interface to match with firebase admin v12 (#1517).
-- Make bucket parameterizeable in storage functions (#1518)
-- Introduce helper library for select and multi-select input (#1518)