This plugin is part of the community.general collection (version 4.2.0).
You might already have this collection installed if you are using the ansible package. It is not included in ansible-core. To check whether it is installed, run ansible-galaxy collection list.
To install it, use:
ansible-galaxy collection install community.general.
To use it in a playbook, specify: community.general.timezone.
ansible-playbook -i inventory ntp_playbook.yml --u kadmin --ask-become-pass