downgrade grunt-bump to support older grunt release
downgrade grunt-bump to support older grunt release

0.6 is the last release to support grunt@0.4.5 - so for now it's better
to stick with that version.

A larger update will follow in one of the next releases.

Open-Xchange-Frontend/generator-ox-ui-module,Open-Xchange-Frontend/generator-ox-ui-module