Tests: Ruby hook tests unstable for version older 3.0

It can fail with reporting following alert:

[alert] 137462#137462 mount("none", "/tmp/unit-test-636e0uh8/proc", "proc", 2097162, "") (16: Device or resource busy)

test/test_ruby_hooks.py

@@ -1,8 +1,11 @@
 from unit.applications.lang.ruby import ApplicationRuby
 from unit.option import option
 from unit.utils import waitforglob
+from packaging import version
 
-prerequisites = {'modules': {'ruby': 'all'}}
+prerequisites = {
+    'modules': {'ruby': lambda v: version.parse(v) >= version.parse('3.0')}
+}
 
 client = ApplicationRuby()