Bump version prefix to 1.20.1 (#633)

* Bump version prefix to 1.20.1

* Add version 1.20.1 and 1.20.0 to changelog

Update changelog to include version 1.20.1 and 1.20.0 changes.

Author: nytian

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changelog
 
+## 1.20.1
+- Fix GrpcChannel handle leak in AzureManaged backendby nytian ([#629](https://github.com/microsoft/durabletask-dotnet/pull/629))
+
 ## 1.20.0
 - Partial orchestration workitem completion support (merge after next dts dp release) by wangbill ([#514](https://github.com/microsoft/durabletask-dotnet/pull/514))
 - Export history job by wangbill ([#494](https://github.com/microsoft/durabletask-dotnet/pull/494))
@@ -394,3 +397,4 @@ Initial public release
 
 
 
+

eng/targets/Release.props

@@ -17,7 +17,7 @@
   </PropertyGroup>
 
   <PropertyGroup>
-    <VersionPrefix>1.20.0</VersionPrefix>
+    <VersionPrefix>1.20.1</VersionPrefix>
     <VersionSuffix></VersionSuffix>
   </PropertyGroup>