Update references to the main branch
Conflicts:
.github/CONTRIBUTING.md
website/content/docs/upgrading/instructions/upgrade-to-1-10-x.mdx
The website conflicts seems like it some of the changes on main didn't
make it into the 1.10.x branch, but the content is relevant for 1.10 so
I took the changes from main.
* Add contributing dir with Config file checklist and modify contribution guides
* Apply suggestions from code review
Co-Authored-By: Chris Piraino <cpiraino@hashicorp.com>
Co-authored-by: Chris Piraino <piraino.chris@gmail.com>
* Add a contribution guide and link to it from readme
* Add first pass at testing section for contribution guide
* Format as in README.md
* Add responding to community questions as way to contribute