Refactored the Makefile around github's release workflow.
Refactored the Makefile around github's release workflow.

1. tag
2. download tag tar.gz
3. sign tar.gz

regularfry/chruby,rstacruz/chruby-fish,kbrock/chruby,eunomie/chgo,ngpestelos/chruby,ilikepi/chruby,ilikepi/chruby,kbrock/chruby,ngpestelos/chruby,rstacruz/chruby-fish,postmodern/chruby,JeanMertz/chruby-fish,postmodern/chruby,JeanMertz/chruby-fish,regularfry/chruby,eunomie/chgo