Adjust rake tasks to update rspec and rspec-dev with CoC changes

[cupakromer]

It would be great to get our rake task updated so that any changes to our CoC are propagated to both rspec/rspec and rspec/rspec-dev.

Related, perhaps we should include the CONTRIBUTING.md files as well. Though these repos work slightly differently so perhaps we need to adjust them a little.

[cupakromer]

Is there a reason our CoC file is all lower case but the other markdown files are upper case? It seems we tend to favor upper case filenames for these sorts of files.

[JonRowe]

I think the the other two just follow the Github convention for those files, we have more .md files with lower case as part of our docs in features/

[myronmarston]

It's accidental, and I've thought about changing it to upper case, too. The CoC was the first file and I didn't think much about it. Then I modeled the the contributing.md and development.md after bundler's files and they use uppercase for those and so I did.

I think I'd prefer they were all uppercase but didn't want to put the effort into fixing it. If someone wants to go for it, that'd be great.