updated manifest to have 1.5
updated manifest to have 1.5

hpcloud/go-buildpack,loafoe/go-buildpack,Jonty/go-buildpack,half-ogre/go-buildpack,half-ogre/go-buildpack,loafoe/go-buildpack,venicegeo/go-pdal-buildpack,half-ogre/go-buildpack,hpcloud/go-buildpack,hpcloud/go-buildpack,loafoe/go-buildpack,cloudfoundry/go-buildpack,cloudfoundry/go-buildpack,venicegeo/go-pdal-buildpack,Jonty/go-buildpack,Jonty/go-buildpack,cloudfoundry/go-buildpack,venicegeo/go-pdal-buildpack