bump version

remove -rc3 from version

Merge pull request splitio#80 from splitio/development

Development

update changelog and version number

version number and CHANGES.txt update

bump version and update CHANGES.txt

Bump version number and update CHANGES.txt

bump version number to 5.2.1 and update CHANGES.txt

bump version to 5.2.0

Merge pull request splitio#66 from splitio/DependencyMatcher

Dependency matcher: Merging for release 5.1.0