Updated for jwtap 1.2.0
Updated for jwtap 1.2.0

* Use v1.2.0-homebrew instead of v1.2.0 as that tag has the fixed install_ngx_mruby.sh which again
  allows overriding enviroment variables by this formula
* Added NGX_MRUBY* environment variables needed to compile mrbgems
  See https://github.com/DaveWillkomm/jwtap/commit/6943bc10e475511a3f4e085a7bfc1ee5573a2bea

dinosaurjr10/homebrew-tap