Update workflows using Ubuntu 20.04 (focal)

[Buristan]

Ubuntu 20.04 will soon be deprecated and unsupported in the GitHub infrastructure.

See also: actions/runner-images#11101

So, we should update workflows, like reusable_testing.yml workflow which is used in the integraion Tarantool testing.
I suppose we can update it up to 24.04 (noble).

Needed for tarantool/tarantool#11220