Both architectures don't have a rust package in Alpine, therefore
squeekboard cannot be built. I did not notice this before, because the
phosh dir was not explicitly listed for building packages in the binary
repository. Instead, only postmarketos-ui-phosh was built with all
depends for all arches, but this package does not depend on squeekboard.
[ci:skip-vercheck]: only arch was changed
Squeekboard is going to replace virtboard in Phosh. However, it requires
Rust which hasn't yet been packaged on Alpine Linux for aarch64. So for
now, keep virtboard as the default (it still works fine) and update it
to the latest commit (see follow-up patch), but also introduce
squeekboard so we can test it and eventually enabled it for aarch64 and
replace virtboard.
