v2.0.0

There are no breaking changes in this release, but it has been marked as a major change due to the significant difference in the underlying tooling. Both source map upload and registering new builds is now done via the @bugsnag/cli package.

• Migrate @bugsnag/source-maps to @bugsnag/cli (#91)
• Migrate @bugsnag/build-reporter to @bugsnag/cli (#91)