ACR Beta2 Changelog updates (Azure#20966)

* beta2 changelog

* update changelog

* more updates

sdk/containerregistry/Azure.Containers.ContainerRegistry/CHANGELOG.md

@@ -1,6 +1,19 @@
 # Release History
 
-## 1.0.0-beta.2 (Unreleased)
+## 1.0.0-beta.3 (Unreleased)
+
+## 1.0.0-beta.2 (2021-05-11)
+
+### Features Added
+- Added support for accessing ACR anonymously via two new constructors on `ContainerRegistryClient`.
+- Added caching of the ACR refresh token during the authentication token exchange to reduce per operation network calls to the service.
+- Updated API to have a single client as an entry point, `ContainerRegistryClient`, with two helper classes, `ContainerRepository` and `RegistryArtifact`, for resource-specific service calls.
+- Added strongly typed string constants for `ArtifactArchitecture` and `ArtifactOperatingSystem`.
+- Renamed methods operating on a manifest to have `Manifest` in their names.
+
+### Breaking Changes
+- Removed `ContainerRepositoryClient`.
+- Renamed `GetRepositories` to `GetRepositoryNames` on `ContainerRegistryClient`.
 
 ## 1.0.0-beta.1 (2021-04-06)
 - Started changelog to capture release notes.