Bump Microsoft.NET.Test.Sdk from 17.14.1 to 18.0.0

---
updated-dependencies:
- dependency-name: Microsoft.NET.Test.Sdk
  dependency-version: 18.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

test/OpenPolicyAgent.Opa.AspNetCore.Tests/OpenPolicyAgent.Opa.AspNetCore.Tests.csproj

@@ -12,7 +12,7 @@
   <!-- Normal Package Includes. -->
   <ItemGroup>
     <PackageReference Include="Microsoft.AspNetCore.TestHost" Version="8.0.20" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.0" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
     <PackageReference Include="Testcontainers" Version="4.7.0" />
     <PackageReference Include="xunit" Version="2.9.3" />