Added changelog and updated annoucement in README.md

Author: Swasti Gupta

CHANGELOG.md

@@ -6,6 +6,7 @@
 * Removed the deprecated MSALLogger interface and implementation class (#2591)
 * Enforced a valid broker-capable redirect URI format for AAD scenarios (#2592)
 * Merged the MSALAccount (MultiTenantAccount) category into the MSALAccount protocol and removed the MSALAccount+MultiTenantAccount.h (#2594)
+* Added a [MSAL 2.x Migration Guide](./docs/MSAL_2x_Migration_Guide.md) to assist developers in upgrading from MSAL 1.x to 2.x. (#2614)
 
 ## [1.9.0]
 * Add feature flags provider to be controlled from broker (#2540)

README.md

@@ -6,6 +6,8 @@ Microsoft Authentication Library for iOS and macOS
 |-------------------------------|---------------------------|-------------------|---------|----------|
 | [MSAL iOS and macOS documentation](https://learn.microsoft.com/en-us/entra/msal/objc/) | &#8226;  [Microsoft Entra ID (workforce samples)](https://learn.microsoft.com/en-us/entra/identity-platform/sample-v2-code?tabs=framework#ios)<br/>&#8226; [Microsoft Entra External ID (customer samples)](https://learn.microsoft.com/en-us/entra/external-id/customers/samples-ciam-all?tabs=apptype#mobile)          | [ SDK reference](https://azuread.github.io/microsoft-authentication-library-for-objc/)             | [Get support](README.md#community-help-and-support) | [Feedback](https://forms.office.com/r/xuBV0CzEih) |
 
+> ⚠️ **MSAL 2.x Released with Breaking Changes**  
+> Please review the [MSAL 2.x for iOS/macOS – Major Release Announcement & Migration Guide](./docs/MSAL_2x_Migration_Guide.md) for full details on what changed and how to migrate.
 
 The Microsoft Authentication Library (MSAL) for iOS and macOS is an auth SDK that can be used to seamlessly integrate authentication into your apps using industry standard OAuth2 and OpenID Connect. It allows you to sign in users or apps with Microsoft identities. These identities include Microsoft Entra ID work and school accounts, personal Microsoft accounts, social accounts, and customer accounts.