.github/workflows: Add multiarch GitHub CI build support
.github/workflows: Add multiarch GitHub CI build support

This adds multiarch build for GitHub bot. Currently, only GCC that
supports multiarch build. I couldn't find the clang cross compiler
package from the Ubuntu apt, so let's skip it at the moment.

New arch supports:
  - aarch64
  - arm (32-bit)

Signed-off-by: Ammar Faizi <a8266392a329a5c7b5ab982a8996391d75b6438e@gnuweeb.org>

axboe/liburing,axboe/liburing,axboe/liburing