the README example code is broken

I'm brand new to gleam and tried to use the code from the readme file and it has a lot of errors and warnings.

1. a minor warning about a Transitive dependency on gleam_http - fixed by explicitly adding gleam_http
2. an unused import of "gleeunit/should"
3. a stray closing-paren after the final assert causes an error
4. i think there is a missing last line to set the return type, which after some archeology into the file history, should be "Ok(response)" - I'm not really sure, but I think this is from the use response <- .... as I said, i'm just learning and have not really got a firm understanding of this language feature.