Update maintainers and community call details.

[Simon Waight (sjwaight)]

This pull request updates the README.md to improve clarity and accuracy regarding project maintainers and community calls. The main changes include providing a direct link to the maintainers list and updating details about the community call schedule and terminology.

Project information updates:

• Added a direct link to the list of maintainers in the main repository by referencing maintainers.md.

Community call information updates:

• Changed the section title from "Community meetings" to "Community calls" and updated the time zone from "ANZ/Asia" to "APAC" for greater accuracy.
• Combined the schedule and recordings sections for community calls into a single section for better organization.