Bump Microsoft.NET.Test.Sdk from 18.6.0 to 18.7.0 (#338)

---
updated-dependencies:
- dependency-name: Microsoft.NET.Test.Sdk
  dependency-version: 18.7.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]

Directory.Packages.props

@@ -38,7 +38,7 @@
     </ItemGroup>
 
     <ItemGroup Label="Tests">
-        <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.6.0"/>
+        <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.7.0"/>
         <PackageVersion Include="Unquote" Version="7.0.1"/>
         <PackageVersion Include="xunit" Version="2.9.3"/>
         <PackageVersion Include="xunit.runner.visualstudio" Version="3.1.5"/>