Switch to the new Tinkerbell Community mailing lists

[Tinkerbell Contributors]

The Tinkerbell Google Groups mailing list is being replaced with new mailing lists maintained by the CNCF:

- Users https://lists.cncf.io/g/cncf-tinkerbell-users

  (hobbyists, casual observers, Community call participants)

- Developers https://lists.cncf.io/g/cncf-tinkerbell-dev 

  (contributors, Maintainers, Triage Party participants)

Please enroll in the new lists that fit your level of interest. Search "tinkerbell" at https://www.cncf.io/calendar/ to find the bi-weekly community calls (archived on YouTube).

Also, be sure to join the CNCF Slack #tinkerbell channel (https://slack.cncf.io/) for real-time conversation. 

If you are headed to KubeCon/CloudNativeCon Detriot 2022, check out Katie Gamanji's talk "Bare-Metal Chronicles: Intertwinement Of Tinkerbell, Cluster API And GitOps".