docs: remove the changelog (#1464)

* Delete CHANGELOG.md * Update PULL_REQUEST_TEMPLATE.md

Author: jimmywarting

.github/PULL_REQUEST_TEMPLATE.md

@@ -12,12 +12,10 @@
 ___
 
 <!-- Mark the ones you have done and remove unnecessary ones. Add new tasks that fit (like TODOs). -->
-- [ ] I updated ./docs/CHANGELOG.md with a link to this PR or Issue
-- [ ] I updated ./docs/v3-UPGRADE-GUIDE
 - [ ] I updated readme
 - [ ] I added unit test(s)
 
 ___
 
-<!-- Add `- Fixes #_NUMBER_` line for every PR/Issue this PR solves. Do not comma separate them. -->
-- Fixes #000
+<!-- Add `- fix #_NUMBER_` line for every PR/Issue this PR solves. Do not comma separate them. -->
+- fix #000