Use updated fast-export

The new mercurial library from Python does not require the use of "repo".
The old fast-export uses "repo" and this causes it to fail.

https://github.com/sessyargc/fast-export.git
 -> https://github.com/frej/fast-export

Tested on a local homebrew env

Signed-off-by: Rommel G Custodio <sessyargc@gmail.com>