src/poky:python3-git: upgrade 3.1.24 -> 3.1.26

Changelog:
=========
Fixes a leaked file descriptor when reading the index, which would cause make
writing a previously read index on windows impossible.
See gitpython-developers/GitPython#1395 for details.

(From OE-Core rev: d0f3d4b0da85ee8d46c6aa069c9bcbceb4f4edf5)

Signed-off-by: Wang Mingyu <[email protected]>
Signed-off-by: Richard Purdie <[email protected]>

Author: wangmingyu84