Upgrade Client to Netbox v2.11

What's Changed

• build with go1.15 by @kobayashi in #97
• Make enforce_unique flag for VRF a pointer by @abhide in #88
• Fix schema for connected_endpoint property of Interface by @DSpeichert in #110
• Fix issue #103 by @smutel in #104
• Netbox v2.11.11 Client Update by @tagur87 in #119

New Contributors

• @abhide made their first contribution in #88
• @DSpeichert made their first contribution in #110
• @tagur87 made their first contribution in #119

Full Changelog: netbox_v2.9...netbox_v2.11