Add weekly learning posts to correct channels

[joekr]

I would like to ingest the learning emails we all signup for (aka https://pycoders.com/issues/416) and post them to the correct channels.

• Python: https://pycoders.com
• Go: https://golangweekly.com
• Ruby: https://rubyweekly.com/
• Rust: https://this-week-in-rust.org/
• JavaScript: https://javascriptweekly.com/
• Flutter: https://flutterweekly.net/

Other considerations:

• https://morningcupofcoding.com/