[Fixes #70438882] Don't pin gem versions

Don't specify the versions that this meta-gem installs.

By not specifying the versions, new users of vCloud Tools will install
the latest available versions of the tools and we avoid having to
increment the versions each time a gem is updated.

* * *
Additionally, include the vCloud Tools Tester gem as a development dependency and bump the version to 1.0.0.

Supersedes #190.