a6b6b7aa4e
As stated [here](https://doc.rust-lang.org/std/io/trait.BufRead.html#errors-1), `read_until` (and `read_line`) ignore Ctrl+C, so Topgrade does not respond to Ctrl+C in the retry prompt, and instead will exit only when enter is pressed after Ctrl+C. This is undesirable, so this pull request is a WIP until we find a solution.