Disable tests that require random feature

Signed-off-by: Michel Lind <salimma@fedoraproject.org>

rust-convert_case.spec

@@ -91,7 +91,8 @@ use the "random" feature of the "%{crate}" crate.
 
 %if %{with check}
 %check
-%cargo_test
+# these tests depend on the `random` feature
+%cargo_test -- -- --skip case::Case::PseudoRandom --skip case::Case::Random --skip pattern::Pattern::PseudoRandom
 %endif
 
 %changelog