Bump Newtonsoft.Json from 8.0.3 to 13.0.1 in /OwinOAuthProvidersDemo

Bumps [Newtonsoft.Json](https://github.com/JamesNK/Newtonsoft.Json) from 8.0.3 to 13.0.1.
- [Release notes](https://github.com/JamesNK/Newtonsoft.Json/releases)
- [Commits](https://github.com/JamesNK/Newtonsoft.Json/compare/8.0.3...13.0.1)

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

Signed-off-by: dependabot[bot] <support@github.com>

OwinOAuthProvidersDemo/packages.config

@@ -24,7 +24,7 @@
   <package id="Microsoft.Owin.Security.Twitter" version="3.0.1" targetFramework="net45" />
   <package id="Microsoft.Web.Infrastructure" version="1.0.0.0" targetFramework="net45" />
   <package id="Modernizr" version="2.8.3" targetFramework="net45" />
-  <package id="Newtonsoft.Json" version="8.0.3" targetFramework="net45" />
+  <package id="Newtonsoft.Json" version="13.0.1" targetFramework="net45" />
   <package id="Owin" version="1.0" targetFramework="net45" />
   <package id="Respond" version="1.4.2" targetFramework="net45" />
   <package id="WebGrease" version="1.6.0" targetFramework="net45" />