Updated CHANGELOG and README ahead of KV Keys beta release. (Azure#41341)

Author: vcolin7

sdk/keyvault/azure-security-keyvault-keys/CHANGELOG.md

@@ -1,16 +1,16 @@
 # Release History
 
-## 4.9.0-beta.1 (Unreleased)
+## 4.9.0-beta.1 (2024-07-29)
 
 ### Features Added
 - Added a new configuration flag to cryptography clients to defer all cryptographic operations to the Key Vault service. ([#40384](https://github.com/Azure/azure-sdk-for-java/pull/40384))
 
-### Breaking Changes
-
-### Bugs Fixed
-
 ### Other Changes
 
+#### Dependency Updates
+
+- Upgraded `azure-core` from `1.49.1` to version `1.50.0`.
+- Upgraded `azure-core-http-netty` from `1.15.1` to version `1.15.2`.
 
 ## 4.8.5 (2024-06-27)
 
@@ -21,7 +21,6 @@
 - Upgraded `azure-core` from `1.49.0` to version `1.49.1`.
 - Upgraded `azure-core-http-netty` from `1.15.0` to version `1.15.1`.
 
-
 ## 4.8.4 (2024-05-13)
 
 ### Other Changes

sdk/keyvault/azure-security-keyvault-keys/README.md

@@ -45,7 +45,7 @@ If you want to take dependency on a particular version of the library that is no
 <dependency>
     <groupId>com.azure</groupId>
     <artifactId>azure-security-keyvault-keys</artifactId>
-    <version>4.8.4</version>
+    <version>4.9.0-beta.1</version>
 </dependency>
 ```
 [//]: # ({x-version-update-end})