Bump Microsoft.NET.Test.Sdk from 18.5.1 to 18.6.0 (#393)

---
updated-dependencies:
- dependency-name: Microsoft.NET.Test.Sdk
  dependency-version: 18.6.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]

GraphOrgExample.Test/GraphOrgExample.Test.csproj

@@ -7,7 +7,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.5.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.6.0" />
     <PackageReference Include="xunit" Version="2.9.3" />
     <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>