net-mgmt/py-ciscoconfparse: Update to 1.5.28

Changelog since 1.5.24:

• Enhance "ccp_util.CiscoRange()" to parse a wider variety of string inputs
• Remove slow code from "ccp_util.CiscoRange()"
• Make "ccp_util.L4Object().repr()" more friendly
• Use "unittest.mock" for tests if available
• Fix the issue with the "L4Object_asa_{lt01,lt02,range}" tests
• Fix multiple unreported bugs in "ccp_util.L4Object()"