README: require ansible-utils >=v4.0.0 or newer when using netaddr >=…

…v1.0.0

relevant part from the netaddr v1.0.0 changelog:
"Remove the IPAddress.is_private method."
https://netaddr.readthedocs.io/en/latest/changes.html#release-1-0-0
https://github.com/ansible-collections/ansible.utils/releases/tag/v4.0.0

related	to #245

README.md

@@ -57,7 +57,7 @@ Control Machine Requirements
 
 - do **not** run this role with `become: yes`
 - tor >= 0.4.8
-- python-netaddr package must be installed
+- python-netaddr package must be installed (ansible-utils version must be >= v4.0.0 if using netaddr >= v1.0.0. See #245)
 - required commands: sort, uniq, wc, cut, sed, xargs
 - openssl >= 1.0.0
 - ansible >= 2.16.4