Contributing.md changes (hackforla#1471)

* Got Akibs Changes

* Update CONTRIBUTING.md file

* Accepted incoming merge conflict

* Made github username wording more consistent

* Added documentation for using Docker back to the file

* Added git status code back to file

* Changed edits to pull request

* Changed wording of issue and pull request headers

* Fixed broken link in edits to a pull request

* Changed wording of first pull request in bottom greeting

* Removed unnecessary text

* Added info about VS Code and moved Changes from Upsream section

* Added hfla-site slack link

* Made changes suggested by alyssa

* Update CONTRIBUTING.md

Minor changes. Made two changes to the file.

Co-authored-by: Josh Bubar <[email protected]>
Co-authored-by: Alyssa <[email protected]>