Add Core Dispatch, update Python Insider

[StanFromIreland]

1. My feed is valid, I checked using https://validator.w3.org/feed/check.cgi?url=MY_FEED_URL and it is valid! (Both https://validator.w3.org/feed/check.cgi?url=https://coredispatch.xyz/api/feed/rss and https://validator.w3.org/feed/check.cgi?url=https://blog.python.org/rss.xml are marked as valid)
2. My feed is a Python Specific feed, e.g: I am proposing the filtered tag or categorized feed url
3. I only post content to this feed which is related to the Python language and its components and libraries. Or content that I consider interesting for the Python community.
4. I am aware that once my feed is added it can take a few hours to start being fetched (according to the server update cycle)
5. My feed contains only content in English language.

[StanFromIreland]

CC @emmatyping and @savannahostrowski

[hugovk]

Thanks!