bump version to 2.6.3

Version bump to 2.6.2

Merge pull request hubotio#533 from github/version-bump-2.6.1

Version bump to 2.6.1

update for v2.5.0 release

* update hubot and hubot-scripts version ranges so it doesn't install 3.0.0

Version bump to 2.5.4

release 2.5.3

Bump package version and 

Bump versions and update CHANGELOG.md

Bump hubot version to 2.5.0

release 2.4.8