Update development status to at-least 'Maintenance fixes only'

Problem/Motivation

As this module has Drupal 9 compatible release, its development status can be marked as Maintenance fixes only instead of No further development. This will help in

• Migrating Drupal 7 users to Drupal 8/9 confidently
• More use of this module for Drupal 8/9

Steps to reproduce

N/A

Proposed resolution

Projects development status can be updated to Maintenance fixes only

Remaining tasks

User interface changes

N/A

API changes

N/A

Data model changes

N/A