add awslimitchecker to list of projects

[jantman]

Per https://github.com/jantman/awslimitchecker/issues/438 the announcement of 2.7 end-of-support will be present in this week's release, along with a PendingDeprecationWarning, and support for all Python versions < 3.5 will be ended on January 1, 2020.

If you're adding a project to the Python 3 statement, please ensure you have:

• [x] Discussed dropping Python 2 support with all maintainers
• [x] Discussed signing the statement with all maintainers
• [ ] Added a suitable logo if the project has one
  • [ ] Approximately square logos generally fit better than banners
  • [ ] Compressed the logo to save bandwidth (run scripts/squash-images.sh on it)
• [x] Checked the Netlify preview made from the pull request

[takluyver]

Thanks, welcome aboard!

(Verified that @jantman is the main maintainer of awslimitchecker)

[jantman]

Thanks so much!