Rev version to 2.1.0-preview.3 and update CHANGELOG (#1249)

Author: TylerLeonhardt

CHANGELOG.md

@@ -1,5 +1,13 @@
 # PowerShell Editor Services Release History
 
+## v2.1.0-preview.3
+### Tuesday, March 31, 2020
+
+- ✨📟 [PowerShellEditorServices #1245](https://github.com/PowerShell/PowerShellEditorServices/pull/1245) -
+  Better PSReadLine version filter check to include 2.1.0+ prereleases.
+- 🐛⚡️🧠🔗 [PowerShellEditorServices #1248](https://github.com/PowerShell/PowerShellEditorServices/pull/1248) -
+  Fix cancellation for completions and add `textDocument/hover` cancellation support.
+
 ## v2.1.0-preview.2
 ### Thursday, March 26, 2020
 

PowerShellEditorServices.Common.props

@@ -1,7 +1,7 @@
 <Project>
   <PropertyGroup>
     <VersionPrefix>2.1.0</VersionPrefix>
-    <VersionSuffix>preview.2</VersionSuffix>
+    <VersionSuffix>preview.3</VersionSuffix>
     <Company>Microsoft</Company>
     <Copyright>© Microsoft Corporation. All rights reserved.</Copyright>
     <PackageTags>PowerShell;editor;development;language;debugging</PackageTags>