Rev version to v2.1.0-preview.4 and update CL (#1254)

Author: TylerLeonhardt

CHANGELOG.md

@@ -1,5 +1,13 @@
 # PowerShell Editor Services Release History
 
+## v2.1.0-preview.4
+### Wednesday, April 08, 2020
+
+- ✨👷 [PowerShellEditorServices #1252](https://github.com/PowerShell/PowerShellEditorServices/pull/1252) -
+  Use PowerShell Daily in CI.
+- 🐛⚡️🧠🔗 [PowerShellEditorServices #1251](https://github.com/PowerShell/PowerShellEditorServices/pull/1251) -
+  Add cancellation to SignatureHelp request and cache results for cmdlets on `Get-Command` and `Get-Help`.
+
 ## v2.1.0-preview.3
 ### Tuesday, March 31, 2020
 

PowerShellEditorServices.Common.props

@@ -1,7 +1,7 @@
 <Project>
   <PropertyGroup>
     <VersionPrefix>2.1.0</VersionPrefix>
-    <VersionSuffix>preview.3</VersionSuffix>
+    <VersionSuffix>preview.4</VersionSuffix>
     <Company>Microsoft</Company>
     <Copyright>© Microsoft Corporation. All rights reserved.</Copyright>
     <PackageTags>PowerShell;editor;development;language;debugging</PackageTags>