Archiving atom-solargraph

[castwide]

Given GitHub's intention to sunset Atom, I expect to archive this project and stop providing updates. Solargraph will continue.

[AlexWayfer]

It can work for https://github.com/atom-community/atom, but it's your desicion.

[castwide]

If anyone wants to fork the project, I'm happy to help pass the torch, such as providing access to update the package or whatever else is necessary for future maintenance.