Bump version to v2.3.0 

2.2.3 

2.2.2 

Merge pull request formatjs#792 from ericf/2.2.1 2.2.1

Merge pull request formatjs#784 from ericf/2.2.0 2.2.0

2.1.5 

2.1.4 

2.1.3 

2.1.2