build: Add commented-out property to disable GitVersion

Useful to use during rebase where you get build failures due to
GitVersion not liking a detached HEAD.

src/Directory.Build.props

@@ -8,6 +8,7 @@
     <DebugType>embedded</DebugType>
     <AnalysisMode>AllEnabledByDefault</AnalysisMode>
     <GitVersionBaseDirectory>$(MSBuildThisFileDirectory)</GitVersionBaseDirectory>
+<!--    <DisableGitVersionTask>true</DisableGitVersionTask>-->
   </PropertyGroup>
 
   <!--