fix: adapt to napalm-device-types 4.7

napalm-device-types 4.7 changed three things this driver depends on:

- parse_dnf_security needs the "__DNF_RC=<status>" line that
  DNF_SECURITY_COMMAND prints and raises ValueError without it or when dnf
  failed. The yum security query had no such line, so listing updates on
  any yum host raised. _YUM_SECURITY_COMMAND now prints the marker the same
  way ("{ ...; echo __DNF_RC=$?; } | cat"). _rpm_security_names checks
  __DNF_RC itself and turns a failed query, or output cut short before the
  marker, into None (security unknown) rather than "no advisories" or an
  exception.
- OSDriver.get_users was renamed to get_os_users, since NAPALM's own
  get_users has another shape. LinuxDriver.get_users is now get_os_users
  with the same return value.
- run_on_transport reads an exec channel to EOF after its exit status
  arrives; the tests' fake channels gain recv/recv_stderr for that.

Require napalm-device-types>=4.7.1 and bump the version to 0.6.0.

tests/test_command_channel.py

@@ -42,9 +42,15 @@ class FakeChannel:
     def recv_ready(self):
         return False
 
+    def recv(self, size):
+        return b""
+
     def recv_stderr_ready(self):
         return False
 
+    def recv_stderr(self, size):
+        return b""
+
     def exit_status_ready(self):
         return True