git-gui: update Russian translation

Translation is done on Transifex: https://www.transifex.com/djm00n/git-po-ru/git-gui/
If you have any corrections please report them there.

Signed-off-by: Dimitriy Ryazantcev <dimitriy.ryazantcev@gmail.com>
Signed-off-by: Pratyush Yadav <me@yadavpratyush.com>

Author: DJm00n