upgrade omnisharp version for test client fix

Author: TylerLeonhardt

src/PowerShellEditorServices/PowerShellEditorServices.csproj

@@ -30,7 +30,7 @@
     <PackageReference Include="Microsoft.CSharp" Version="4.7.0" />
     <PackageReference Include="Microsoft.Extensions.FileSystemGlobbing" Version="3.1.1" />
     <PackageReference Include="Microsoft.Extensions.Logging" Version="3.1.1" />
-    <PackageReference Include="OmniSharp.Extensions.LanguageServer" Version="0.14.2" />
+    <PackageReference Include="OmniSharp.Extensions.LanguageServer" Version="0.15.0" />
     <PackageReference Include="PowerShellStandard.Library" Version="5.1.1" />
     <PackageReference Include="Serilog" Version="2.9.0" />
     <PackageReference Include="Serilog.Extensions.Logging" Version="3.0.1" />
@@ -40,6 +40,6 @@
     <PackageReference Include="System.Security.Principal" Version="4.3.0" />
     <PackageReference Include="System.Security.Principal.Windows" Version="4.7.0" />
     <PackageReference Include="UnixConsoleEcho" Version="0.1.0" />
-    <PackageReference Include="OmniSharp.Extensions.DebugAdapter.Server" Version="0.14.2" />
+    <PackageReference Include="OmniSharp.Extensions.DebugAdapter.Server" Version="0.15.0" />
   </ItemGroup>
 </Project>

src/PowerShellEditorServices/Services/TextDocument/Handlers/CodeActionHandler.cs

@@ -5,8 +5,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Diagnostics;
-using System.Runtime.InteropServices;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;

test/PowerShellEditorServices.Test.E2E/PowerShellEditorServices.Test.E2E.csproj

@@ -10,7 +10,7 @@
     <PackageReference Include="Microsoft.Extensions.Logging" Version="3.1.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.4.0" />
     <PackageReference Include="Newtonsoft.Json" Version="12.0.2" />
-    <PackageReference Include="OmniSharp.Extensions.LanguageClient" Version="0.14.2" />
+    <PackageReference Include="OmniSharp.Extensions.LanguageClient" Version="0.15.0" />
     <PackageReference Include="xunit" Version="2.4.0" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.0" />
   </ItemGroup>