Adjust regex for VRF to include IOSXR config style

[mjohnste]

Adjust the vrf() property method to include a regex which matches IOSXR style VRF interface definition.

@property
def vrf(self):
    retval = self.re_match_iter_typed(
        r"^\s*(ip\s+)*vrf\sforwarding\s(\S+)$", result_type=str, group=2, default=""
    )
    return

The IOSXR VRF interface config is:

interface NAME
 vrf VRFNAME

[mpenning]

I just pushed the new ciscoconfparse/models_iosxr.py to main.

I'm in the middle of preparing for some major feature additions in 1.7.0 so this won't hit pypi for a while yet. Nonetheless, you can get the new models_iosxr.py file from github. I doubt this is going to be useful because I've never focused an effort on iosxr config parsing yet.