Added shellcheck and tailor to plugin list

Added Intrepid Pursuits LLC's danger plugins to the list.

Shellcheck:

• https://github.com/IntrepidPursuits/danger-shellcheck
• https://rubygems.org/gems/danger-shellcheck

Tailor:

• https://github.com/IntrepidPursuits/danger-tailor
• https://rubygems.org/gems/danger-tailor