phosh/squeekboard: disable aarch64, x86

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

phosh/squeekboard/APKBUILD

@@ -5,7 +5,8 @@ pkgver=0_git20190723
 pkgrel=0
 _commit="4b66add65fa7d3875596c108430699a44d98f50e"
 pkgdesc="The final Phosh keyboard"
-arch="all"
+# aarch64, x86: missing rust
+arch="all !aarch64 !x86"
 url="https://source.puri.sm/Librem5/squeekboard"
 license="GPL-3.0-or-later"
 depends=""