Remove python-pip from makedeps

https://github.com/alerque/aur/blob/193c9f4aa112e7fbb07f0b41815155024c34268d/python-skia/PKGBUILD#L13 https://github.com/alerque/aur/blob/193c9f4aa112e7fbb07f0b41815155024c34268d/python-pantable-git/PKGBUILD#L17 https://github.com/alerque/aur/blob/193c9f4aa112e7fbb07f0b41815155024c34268d/python-ttfautohint-py/PKGBUILD#L12 This all should be using `python-installer` which is much simpler and brings less (indirect) dependencies. Related: https://github.com/alerque/aur/pull/98