Add Updated Libraries List To CPy Library Report

[sommersoft]

Add a list of libraries that have been updated in the last 7 days, which kind of coincides with the current insights (issues, PRs, reviews, etc). Also enables an easily accessible list for updating the circuitpython-weekly-newsletter.

"Updated library" is defined as either a newly released library, or a library that has had a new release.

Format will be Markdown, as follows:

Library updates in the last 7 days:
**New Libraries**
* [Library Name](library_url)

**Updated Libraries**
* [Library Name](library_url)

In talking with @kattni, we shared the concern of adding to the length of the already long library report. To address this, we'll remove the list of open library issues and replace it with a link to the CircuitPython Libraries! issue on the core repo. The list is currently 94 lines long.

A secondary effort to have adabot update that issue will be completed, using the GitHub API. This is to replace the above daily reporting of current issues and because the website is not allowing updates on the issue anyway. See #77.