asciidoctor-extensions: remove MinGW Git as build dependency
asciidoctor-extensions: remove MinGW Git as build dependency

Pacman actually insists on using the MSys Git when the sources setting
refers to a Git repository...

Signed-off-by: Johannes Schindelin <53fb8db7833fca1e1746dd8592f61048d350f64c@gmx.de>

git-for-windows/MINGW-packages,vcgato29/MINGW-packages,dscho/MINGW-packages,dscho/MINGW-packages,vcgato29/MINGW-packages,JanSchulz/MINGW-packages,silverkorn/MINGW-packages,JanSchulz/MINGW-packages,JanSchulz/MINGW-packages,git-for-windows/MINGW-packages,silverkorn/MINGW-packages,git-for-windows/MINGW-packages,vcgato29/MINGW-packages,silverkorn/MINGW-packages,dscho/MINGW-packages,dscho/MINGW-packages,dscho/MINGW-packages