Sentry @ 7.x Support

[zackdotcomputer]

Sentry released version 7 today of their JS libraries. These include some breaking changes, primarily the migration to ES6 and the dropping of some exports such as the Severity enum.

Since this just happened, I think there's some leeway for supporting it. But, at some point this library should get an updated version with the necessary changes to allow 7.x as a peer version.