New release of POSHTUI - v0.5

In this release, main feature, is ability to detect ruby version used in project (current directory) and open appropriate ruby docsets.

This is achieved by parsing `Gemfile.lock` from current directory to create list of all gems and rubies in use.

Install update with a following command:

brew update && brew upgrade poshtui

Or install latest version, if it's your first time.

brew tap skatkov/tap && brew install skatkov/tap/poshtui

Next on todo list

Regarding client itself, there is one issue that always comes up in feedback:

- Integrating POSHTUI with code editors, maybe even a plugin for them. This feature might also give me ability to appear in a marketplace and become a good distribution/marketing channel.

My first attempt would be to get this working with VS Code.

There is also a lot of work on docset generation plugin. I need to resolve these issues and figure out how to integrate rdoc plugin with yard.