Bump Microsoft.NET.Test.Sdk from 17.12.0 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
- 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]

DIDemo.Services.Tests/DIDemo.Services.Tests.csproj

@@ -4,7 +4,7 @@
     <IsPackable>false</IsPackable>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.3.0" />
     <PackageReference Include="MSTest.TestAdapter" Version="3.7.0" />
     <PackageReference Include="MSTest.TestFramework" Version="3.7.0" />
   </ItemGroup>

DIDemo.Tests/DIDemo.Tests.csproj

@@ -4,7 +4,7 @@
     <IsPackable>false</IsPackable>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.3.0" />
     <PackageReference Include="MSTest.TestAdapter" Version="3.7.0" />
     <PackageReference Include="MSTest.TestFramework" Version="3.7.0" />
   </ItemGroup>