Danhellem lts update

[danhellem]

Checklist

• [x] I have read the [contribution guidelines] (https://github.com/Azure/azure-iot-sdk-node/blob/master/.github/CONTRIBUTING.md).
• [ ] I added or modified the existing tests to cover the change (we do not allow our test coverage to go down).
• If this is a modification that impacts the behavior of a public API
  • [ ] I edited the corresponding document in the devdoc folder and added or modified requirements.

Reference/Link to the issue solved with this PR (if any)

Description of the problem

Updating LTS content in readme

Description of the solution

[danhellem]

@BertKleewein @anthonyvercolano is the LTS table still correct? We don't need to add anything right?