contributing: clarify how to submit debug output with a new issue
contributing: clarify how to submit debug output with a new issue

Kaixiang/packer,suma/packer,TranscendComputing/packer,Kaixiang/packer,suma/packer,suma/packer,TranscendComputing/packer,TranscendComputing/packer,suma/packer,Kaixiang/packer,Kaixiang/packer,TranscendComputing/packer