message: docs(nextjs): Update README to indicate Next 12 support
  In we added the note as we didn't support Next 12, but now with merged, we can update this.
diff: ## Compatibility
  -Currently, the Sentry Next.js SDK supports Next.js versions `10.0.8` - `11.1.3`. The SDK may work with some projects using Next.js 12, but it is not yet officially supported.
  +Currently, the minimum Next.js supported version is `10.0.8`.
  ## General
  