Post v0.2 release

[varungandhi-src]

I'm moving some of the stuff from the v0.2 post to here (#1), because we've made a number of improvements already, and it would be good to publish a release sooner rather than later.

Language / Sorbet features

• Inheritance related
  • Emit references relationship for method overrides #114
• Hoverdocs
  • hover docs: Fix incorrect 'private' markings in method defs #33
  • 'warnings' text in hover docs #85
  • Generally, we should go through the hoverdocs related issues, and do a bunch of manual testing + fixes.
• Add tests for casts
  • Check that hoverdocs / type info is updated
• Read name and version from Gemfile/gemspec fix: Try to infer gem name and version. #143
• Investigate special-casing the standard library in Sourcegraph. We already have some special-casing for the JDK. With Sorbet, it's even more "weird" because a bunch of the code lives in this repo, so I'm not sure how this would work, but potentially worth exploring...

More testing

• Add tests for RBI files

Nice-to-have

• Add a small CLI reference docs: Add docs for CLI and building from source. #148
• Write references (these aren't used in the UI yet, but we should fix this sooner rather than later)
  • Add write references for array writes
  • Add write references for hash writes
• Default to using . as the directory if one will be needed but is not specified by the config. -- I tried implementing this naively by tweaking option parsing when running as scip-ruby but started getting crashes in builds for some reason which I didn't have time to look into.