Bump Microsoft.NET.Test.Sdk from 18.0.0 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-minor
...

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

Author: dependabot[bot]

tests/NHapi.Base.NUnit/NHapi.Base.NUnit.csproj

@@ -18,7 +18,7 @@
   <ItemGroup>
     <PackageReference Include="NUnit" Version="4.3.2" />
     <PackageReference Include="NUnit3TestAdapter" Version="6.1.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.4.0" />
     <PackageReference Include="TimeZoneConverter" Version="7.2.0" />
 
     <PackageReference Include="coverlet.collector" Version="8.0.0">