Bump Newtonsoft.Json in /test/Spring/Spring.Core.Tests

Bumps [Newtonsoft.Json](https://github.com/JamesNK/Newtonsoft.Json) from 12.0.3 to 13.0.1.
- [Release notes](https://github.com/JamesNK/Newtonsoft.Json/releases)
- [Commits](JamesNK/Newtonsoft.Json@12.0.3...13.0.1)

---
updated-dependencies:
- dependency-name: Newtonsoft.Json
  dependency-type: direct:production
...

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

Author: dependabot[bot]

test/Spring/Spring.Core.Tests/Spring.Core.Tests.csproj

@@ -19,7 +19,7 @@
     <PackageReference Include="FakeItEasy" Version="$(FakeItEasyVersion)" />
     <PackageReference Include="FakeItEasy.Analyzer.CSharp" Version="$(FakeItEasyAnalyzerVersion)" PrivateAssets="All" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="$(MicrosoftTestSDKVersion)" />
-    <PackageReference Include="Newtonsoft.Json" Version="12.0.3" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
     <PackageReference Include="NUnit" Version="$(NUnitVersion)" />
     <PackageReference Include="NUnit3TestAdapter" Version="$(NUnitTestAdapterVersion)" />
     <PackageReference Include="System.Resources.Extensions" Version="5.0.0" />