Bump newtonsoft.json from 12.0.2 to 13.0.1 in /GitLfs.Core

Bumps [newtonsoft.json](https://github.com/JamesNK/Newtonsoft.Json) from 12.0.2 to 13.0.1.
- [Release notes](https://github.com/JamesNK/Newtonsoft.Json/releases)
- [Commits](JamesNK/Newtonsoft.Json@12.0.2...13.0.1)

---
updated-dependencies:
- dependency-name: newtonsoft.json
  dependency-type: direct:production
...

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

Author: dependabot[bot]

GitLfs.Core/GitLfs.Core.csproj

@@ -6,7 +6,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.AspNetCore.Hosting.Abstractions" Version="2.2.0" />
-    <PackageReference Include="newtonsoft.json" Version="12.0.2" />
+    <PackageReference Include="newtonsoft.json" Version="13.0.1" />
     <PackageReference Include="System.ComponentModel.Annotations" Version="4.5.0" />
   </ItemGroup>
 </Project>