knot-resolver: update to version 5.4.0

Should I also update knot in this MR? knot-resolver will have to be rebuilt against it when it gets updated.

I had to disable kres_gen_test, because it fails on cross (lua type of time_t is 8B, but C says it is 4B long). This is probably because musl 1.1 uses 32bit time_t, but lua will report the host's time_t size (which is 8B on new glibcs and musl 1.2). If my guess is correct, I will submit a PR upstream to disable this test on cross. Should it be documented in the Makefile or is adding a patch better, because the next person who updates this package will notice that it's outdated?

Closes #786 (closed)