Bump Newtonsoft.Json from 12.0.3 to 13.0.2 in /FlatFileGenerator

Bumps [Newtonsoft.Json](https://github.com/JamesNK/Newtonsoft.Json) from 12.0.3 to 13.0.2.
- [Release notes](https://github.com/JamesNK/Newtonsoft.Json/releases)
- [Commits](JamesNK/Newtonsoft.Json@12.0.3...13.0.2)

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

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

Author: dependabot[bot]

FlatFileGenerator/FlatFileGenerator.csproj

@@ -16,7 +16,7 @@
 
   <ItemGroup>
     <PackageReference Include="FlatFileGenerator.Core" Version="1.2.1" />
-    <PackageReference Include="Newtonsoft.Json" Version="12.0.3" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.2" />
   </ItemGroup>
 
   <ItemGroup>