Update outdated community & governance pages

[lauriemerrell]

We have a few website pages that contain significantly outdated information. These are pages that we intend to keep so they need updates to be accurate and current.

• /community recommends joining a Google Group that I am not aware of being active any more; it also links to some general open source resources that seem out of date (see Remove outdated content aggregating open source projects & people #569) and lists a bunch of other Chicago civic tech events that are mostly (or all?) inactive
• /governance-meetings lists board meeting information through 2020 but does not contain minutes or agenda links since then