Update artifact-store.md
Update artifact-store.md

The code blocks all look fine in the preview; hopefully the extra spacing will make them render correctly on the site.
meln1k/marathon,janisz/marathon,pgkelley4/marathon,Caerostris/marathon,guenter/marathon,janisz/marathon,mesosphere/marathon,guenter/marathon,gsantovena/marathon,gsantovena/marathon,vivekjuneja/marathon,vivekjuneja/marathon,mesosphere/marathon,meln1k/marathon,titosand/marathon,timcharper/marathon,mesosphere/marathon,meln1k/marathon,janisz/marathon,pgkelley4/marathon,vivekjuneja/marathon,titosand/marathon,guenter/marathon,Caerostris/marathon,natemurthy/marathon,guenter/marathon,gsantovena/marathon,meln1k/marathon,gsantovena/marathon,timcharper/marathon,janisz/marathon,Caerostris/marathon,guenter/marathon,ss75710541/marathon,yp-engineering/marathon,ss75710541/marathon,natemurthy/marathon,timcharper/marathon,meln1k/marathon,janisz/marathon,Caerostris/marathon,yp-engineering/marathon,mesosphere/marathon,ss75710541/marathon,Caerostris/marathon,natemurthy/marathon,gsantovena/marathon,mesosphere/marathon