docker: Do not require checks for libyang Alpine Linux package build

docker: Do not require checks for libyang Alpine Linux package build

Since Alpine Linux 3.20, we get this:

>>> WARNING: libyang: APKBUILD does not run any tests!
    Alpine policy will soon require that packages have any relevant testsuites run during the build process.
    To fix, either define a check() function, or declare !check in $options to indicate the package does not have a testsuite.

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>