EPIC: Automations for increased WG productivity and visibility

As a maintainer for Knative, I appreciate all the existing working group related automations that the project either has in place, or documented, or that existing maintainers are willing to share. In particular, information for upcoming WG update meetings, PR contributions, and support rotation schedule and notification.

However, there is room to ensure new Knative contributors and users are having easy access to relevant project updates, as well as decrease the burden of individual WG leads having to maintain and tweak their own individual ways of gathering information.

Below are tasks for automating the generation and distributing relevant information over a wider reach:

- [ ] [Improve the visibility of the TOC schedule for WG review/update](https://github.com/knative/community/issues/1062)
- [ ] [Improve the visibility of project contributions](https://github.com/knative/community/issues/1063)
- [ ] [Improve the visibility/notification of the support rotation schedule](https://github.com/knative/community/issues/402)

## Proposed list of distribution channels
- Slack: since every working group has a corresponding Slack channel, and [we already have infra](https://github.com/knative-sandbox/knobots/blob/main/README.md#welcome-to-knobots) to post to Slack, this would be an obvious choice. Only the output relevant to each WG should be sent to the corresponding WG channel
- a permanent file in the `community` repo with an aggregate of all WGs
- the Knative Twitter account
- the dev mailing list
- the website

Consideration should be given to approaching this solution as a system, looking for opportunities to extract pieces that can be reused by other tasks.

/Epic

Start by reviewing the linked sub-issues 1062, 1063, and 402, then read the knobots README section on posting to Slack. Define the reusable automation system and decide how its outputs should reach the listed channels and permanent community file; completion requires the scoped sub-issues and distribution approach to be implemented.

Written by the indexing model from the issue text.