Bump Microsoft.NET.Test.Sdk from 17.14.1 to 18.4.0

---
updated-dependencies:
- dependency-name: Microsoft.NET.Test.Sdk
  dependency-version: 18.4.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Philips.CodeAnalysis.Test/Philips.CodeAnalysis.Test.csproj

@@ -11,7 +11,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="3.6.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.4.0" />
     <PackageReference Include="Moq" Version="4.20.72" />
     <PackageReference Include="MSTest.TestAdapter" Version="3.10.4" />
     <PackageReference Include="MSTest.TestFramework" Version="3.10.4" />