Regenerate gemspec for version 0.15.8
Regenerate gemspec for version 0.15.8

edmundhighcock/coderunner,edmundhighcock/coderunner,coderunner-framework/coderunner,edmundhighcock/coderunner,coderunner-framework/coderunner,coderunner-framework/coderunner,coderunner-framework/coderunner