Try a different approach to avoiding spurious NuGet pack issues

Author: nblumhardt

src/Serilog.Extensions.Logging/Serilog.Extensions.Logging.csproj

@@ -18,8 +18,11 @@
     <RepositoryType>git</RepositoryType>
     <DebugType>embedded</DebugType>
     <PublishRepositoryUrl>true</PublishRepositoryUrl>
+    <EmbedUntrackedSources>true</EmbedUntrackedSources>
     <ContinuousIntegrationBuild Condition="'$(APPVEYOR)' == 'true'">True</ContinuousIntegrationBuild>
     <PackageReadmeFile>README.md</PackageReadmeFile>
+    <!-- See https://github.com/NuGet/Home/issues/6001 -->
+    <NoWarn>NU5118</NoWarn>
   </PropertyGroup>
 
   <ItemGroup>