Add info about skip_capture in the update document

Author: Jean85

UPGRADE-3.0.md

@@ -8,6 +8,9 @@ The major change is in the fact that we now require the `sentry/sdk` metapackage
 This new version has been completely rewritten: if you use this bundle and you interact directly with the underlying SDK
 and client, you should read through the [relative upgrade document](https://github.com/getsentry/sentry-php/blob/master/UPGRADE-2.0.md).
 
+The only breaking change reflected in the bundle due to this update is the `skip_capture` option: it has been **removed** because
+the same feature has been implemented in the new SDK, with the native `excluded_exceptions` option.
+
 ## HTTPlug
 Since SDK 2.0 uses HTTPlug to remain transport-agnostic, you need to have installed two packages that provides 
 [`php-http/async-client-implementation`](https://packagist.org/providers/php-http/async-client-implementation)