Update readme to include dns validation

[anhtaiH]

Summary

Updates readme

Description

Related Issue

Motivation and Context

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Automated Testing
• Documentation

Testing Details

Screenshots (if appropriate)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[coveralls]

Coverage increased (+0.04%) to 55.009% when pulling 2880b8d on anhtaiH:documentation into 862627f on Auklets:master.

[coveralls]

Coverage increased (+0.04%) to 55.009% when pulling a483e7f on anhtaiH:documentation into 862627f on Auklets:master.