Update contributing docs#2387

Merged

knative-prow-robot merged 4 commits intoknative:masterfrom

evankanderson:a-contribution

May 26, 2020

Commits on May 6, 2020

Update contributing docs and move back from https://github.com/knative/community
Evan Anderson
committed
Fix misspellings and trailing whitespace
Evan Anderson
committed
Fix broken links
Evan Anderson
committed

Commits on May 14, 2020

Incorporate suggestions from abrennan89
Evan Anderson
committed