Updated CHANGELOG.md to include the migration guide

Author: pmathew92

CHANGELOG.md

@@ -3,6 +3,8 @@
 ## [3.0.0](https://github.com/auth0/Auth0.Android/tree/3.0.0) (2024-10-30)
 [Full Changelog](https://github.com/auth0/Auth0.Android/compare/2.11.0...3.0.0)
 
+Check the [Migration Guide](https://github.com/auth0/Auth0.Android/blob/main/V3_MIGRATION_GUIDE.md) to understand the changes required to migrate your application to v3
+
 **⚠️ BREAKING CHANGES**
 - BREAKING CHANGE: updated description of AuthenticationException in case of empty description [\#756](https://github.com/auth0/Auth0.Android/pull/756) ([desusai7](https://github.com/desusai7))
 - feat: implemented biometrics authentication for SecureCredentialsManager using androidx.biometrics package [\#745](https://github.com/auth0/Auth0.Android/pull/745) ([desusai7](https://github.com/desusai7))