Regenerate gemspec for version 0.12.8
Regenerate gemspec for version 0.12.8

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