Bundle without nproc on CI
Bundle without nproc on CI

nproc is in coreutils which isn't installed by default. Since the
Gemfile is so small there's no real benefit to using -jX anyway.

ttasanen/oga,ttasanen/oga,YorickPeterse/oga,YorickPeterse/oga,ttasanen/oga,ttasanen/oga,YorickPeterse/oga,YorickPeterse/oga,YorickPeterse/oga,ttasanen/oga