Bump Microsoft.NET.Test.Sdk from 17.14.1 to 18.0.0 (#44)

Author: dependabot[bot]

test/Diffs.Test.csproj

@@ -16,7 +16,7 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
     <PackageReference Include="NUnit3TestAdapter" Version="5.1.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.0" />
   </ItemGroup>
 
   <ItemGroup>