[release] Prepare release Sampler.AWS-0.1.0-alpha.3 (open-telemetry#2412)

Author: opentelemetrybot

src/OpenTelemetry.Sampler.AWS/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+## 0.1.0-alpha.3
+
+Released 2024-Dec-12
+
 * Drop support for .NET 6 as this target is no longer supported and add .NET 8 target.
   ([#2172](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/2172))