docs: Pull contributing document from v1 branch (#3270)
docs: Pull contributing document from v1 branch (#3270)

* docs: Pull contributing document from v1 branch

* Update .github/CONTRIBUTING.md

Co-Authored-By: Matt Holt <6e15340bc34d98c823445cca0475cc9127379d4b@users.noreply.github.com>

* docs: [Responsible -> Coordinated] Disclosure

* docs: Link to the new security policy page

Co-authored-by: Matt Holt <6e15340bc34d98c823445cca0475cc9127379d4b@users.noreply.github.com>
mholt/caddy,abiosoft/caddy,l3dlp/caddy,mholt/caddy,l3dlp/caddy,abiosoft/caddy,l3dlp/caddy