Bump Microsoft.NET.Test.Sdk from 17.14.1 to 18.3.0

---
updated-dependencies:
- dependency-name: Microsoft.NET.Test.Sdk
  dependency-version: 18.3.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

tests/Dotnet.CI.Template.Sample.Tests/Dotnet.CI.Template.Sample.Tests.csproj

@@ -6,7 +6,7 @@
 
   <ItemGroup>
     <PackageReference Include="coverlet.collector" Version="8.0.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.3.0" />
     <PackageReference Include="xunit" Version="2.9.3" />
     <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5" />
   </ItemGroup>