Increment version for data/azappconfig releases (Azure#19397)

Increment package version after release of data/azappconfig

Author: azure-sdk

sdk/data/azappconfig/CHANGELOG.md

@@ -1,5 +1,15 @@
 # Release History
 
+## 0.4.3 (Unreleased)
+
+### Features Added
+
+### Breaking Changes
+
+### Bugs Fixed
+
+### Other Changes
+
 ## 0.4.2 (2022-10-20)
 
 ### Bugs Fixed