Fix and improve vcpkg_update.py script - #144

Fix and improve vcpkg_update.py script#144

JoergAtGithub wants to merge 2 commits into

daschuer:vcpkg_updatedaschuer/mixxx:vcpkg_updatefrom

JoergAtGithub:vcpkg_update_windows_fixJoergAtGithub/mixxx:vcpkg_update_windows_fixCopy head branch name to clipboard