Update Newtonsoft.Json from 12.0.1 to 12.02 (latest version), which increases the minimum PS Core version from 6.2.0 to 6.2.1

[bergmeister]

PR Summary

Update Newtonsoft.Json from 12.0.1 to 12.02 (latest version), which increases the minimum PS Core version from 6.2.0 to 6.2.1
Since 6.2.0 has already been superseded by newer patch releases, this is OK.

For a proof of this, see the source code here: https://github.com/PowerShell/PowerShell/blob/v6.2.1/src/System.Management.Automation/System.Management.Automation.csproj#L12

PR Checklist

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• Summarized changes
• Change is not breaking
• Make sure all .cs, .ps1 and .psm1 files have the correct copyright header
• Make sure you've added a new test if existing tests do not effectively test the code changed and/or updated documentation
• This PR is ready to merge and is not Work in Progress.
  • If the PR is work in progress, please add the prefix WIP: to the beginning of the title and remove the prefix when the PR is ready.