Fix regex in release script
Fix regex in release script

Update regex to accept version numbers in the form 1.2.0devX as well as 1.2.0-devX

Testing Done:
https://travis-ci.org/pantsbuild/pants/builds/159386910

Manually verified that regex correctly pulls in the latest release.

Bugs closed: 3858

Reviewed at https://rbcommons.com/s/twitter/r/4226/

tdyas/pants,foursquare/pants,cevaris/pants,cevaris/pants,UnrememberMe/pants,landism/pants,UnrememberMe/pants,15Dkatz/pants,benjyw/pants,kwlzn/pants,pantsbuild/pants,pantsbuild/pants,pantsbuild/pants,tdyas/pants,twitter/pants,lahosken/pants,twitter/pants,lahosken/pants,cevaris/pants,landism/pants,cevaris/pants,pantsbuild/pants,benjyw/pants,pantsbuild/pants,benjyw/pants,UnrememberMe/pants,baroquebobcat/pants,benjyw/pants,kwlzn/pants,UnrememberMe/pants,twitter/pants,UnrememberMe/pants,tdyas/pants,twitter/pants,peiyuwang/pants,cevaris/pants,lahosken/pants,landism/pants,baroquebobcat/pants,landism/pants,fkorotkov/pants,wisechengyi/pants,kwlzn/pants,15Dkatz/pants,15Dkatz/pants,ericzundel/pants,wisechengyi/pants,pantsbuild/pants,landism/pants,cevaris/pants,foursquare/pants,pantsbuild/pants,pombredanne/pants,kwlzn/pants,cevaris/pants,wisechengyi/pants,jsirois/pants,twitter/pants,tdyas/pants,15Dkatz/pants,wisechengyi/pants,ericzundel/pants,pombredanne/pants,tdyas/pants,15Dkatz/pants,lahosken/pants,lahosken/pants,ericzundel/pants,benjyw/pants,mateor/pants,foursquare/pants,fkorotkov/pants,peiyuwang/pants,pombredanne/pants,twitter/pants,benjyw/pants,wisechengyi/pants,mateor/pants,fkorotkov/pants,kwlzn/pants,benjyw/pants,UnrememberMe/pants,jsirois/pants,wisechengyi/pants,foursquare/pants,tdyas/pants,wisechengyi/pants,mateor/pants,tdyas/pants,tdyas/pants,lahosken/pants,baroquebobcat/pants,baroquebobcat/pants,tdyas/pants,15Dkatz/pants,fkorotkov/pants,wisechengyi/pants,mateor/pants,ericzundel/pants,fkorotkov/pants,baroquebobcat/pants,baroquebobcat/pants,mateor/pants,peiyuwang/pants,kwlzn/pants,fkorotkov/pants,UnrememberMe/pants,lahosken/pants,foursquare/pants,pombredanne/pants,foursquare/pants,landism/pants,jsirois/pants,foursquare/pants,kwlzn/pants,mateor/pants,fkorotkov/pants,twitter/pants,baroquebobcat/pants,peiyuwang/pants,pombredanne/pants,UnrememberMe/pants,ericzundel/pants,wisechengyi/pants,landism/pants,ericzundel/pants,twitter/pants,fkorotkov/pants,baroquebobcat/pants,foursquare/pants,mateor/pants,ericzundel/pants,mateor/pants,lahosken/pants,15Dkatz/pants,pombredanne/pants,landism/pants,UnrememberMe/pants,foursquare/pants,peiyuwang/pants,twitter/pants,peiyuwang/pants,pombredanne/pants,baroquebobcat/pants,15Dkatz/pants,peiyuwang/pants,ericzundel/pants,peiyuwang/pants