Add rust manchester august online meetup

Author: jamesfielder

draft/2021-08-04-this-week-in-rust.md

@@ -128,6 +128,7 @@ decision. Express your opinions now.
 
 * [August 3, 2021, Buffalo, NY, US - Buffalo Rust User Group, First Tuesdays - Buffalo Rust Meetup](https://www.meetup.com/Buffalo-Rust-Meetup/events/jxfdjsycclbfb/)
 * [August 9, 2021, Seattle, WA, US - Monthly meetup - Seattle Rust Meetup](https://www.meetup.com/Seattle-Rust-Meetup/events/gskksrycclbnb/)
+* [August 19, 2021, Manchester, UK - Rust Manchester - Speeding Up the Snake: Extending Python with Rust](https://www.meetup.com/rust-manchester/events/279730616/)
 
 ### North America