abuild: pass --no-warnings to apk index

Merged Ghost User requested to merge (removed):indexwarn into master

apk 2.14 now warns on missing deps in the same repo even with --quiet:

WARNING: No provider for the dependencies: /bin/sh aardvark-dns abseil-cpp-dev acl acl-dev alsa-lib-dev android-tools aom-dev apache2 at-spi2-core at-spi2-core-dev atomicparsley attr attr-dev audacious autoconf avahi avahi-dev aws-c-cal-dev aws-c-compression-dev aws-checksums-dev baloo-dev bash bc binutils binutils-dev black blas-dev bluez

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