Allow any ..Component.CoreEditor version

Changed [15.0.25824.0,16.0) to [15.0.25824.0,) for
Microsoft.VisualStudio.Component.CoreEditor.

Author: jcansdale

src/GitHub.VisualStudio/source.extension.vsixmanifest

@@ -39,6 +39,6 @@
     <Asset Type="Microsoft.VisualStudio.MefComponent" d:Source="File" Path="Rothko.dll" />
   </Assets>
   <Prerequisites>
-    <Prerequisite Id="Microsoft.VisualStudio.Component.CoreEditor" Version="[15.0.25824.0,16.0)" DisplayName="Visual Studio core editor" />
+    <Prerequisite Id="Microsoft.VisualStudio.Component.CoreEditor" Version="[15.0.25824.0,)" DisplayName="Visual Studio core editor" />
   </Prerequisites>
 </PackageManifest>