Update RELEASENOTES.md

Merge pull request #2436 from salesforce-ux/release-v2.3.0

Get 2.3.0 ready for prime time

Merge pull request #1927 from salesforce-ux/hotfix/control-docsearch-…

…config-through-packagejson

Fix search and control DocSearch configuration through package.json

Merge pull request #1883 from salesforce-ux/chore/get-ready-for-prime…

…-time

Get 2.2.0 ready for prime time

2.1.4

2.1.3

2.1.2

2.0.3

2.0.2