Compatibility with Mercurial 6.1

Thg cannot start with Mercurial 6.1.

    #!python
    ** Mercurial version (6.1).  TortoiseHg version (6.0)
    ** Command: --help
    ** CWD: /home/kea/src/nixpkgs
    ** Encoding: UTF-8
    ** Extensions loaded: 
    ** Python version: 3.9.10 (main, Jan 13 2022, 23:32:03) [GCC 10.3.0]
    ** System: Linux box 5.10.96 #1-NixOS SMP Tue Feb 1 16:25:48 UTC 2022 x86_64
    ** Qt-5.15.3 PyQt-5.15.4 QScintilla-2.13.1
    
    This version of TortoiseHg requires Mercurial version 5.9.n to 6.0.n, but found 6.1