net-mgmt/py-junos-eznc: Update to 2.7.0

• There is already version 2.7.1, which was deliberately not chosen because it pulls in a custom patched module of py-paramiko 3.4.0 during build/installation.

Changelog since 2.6.4:

https://github.com/Juniper/py-junos-eznc/blob/2.7.0/RELEASE-NOTES.md

PR: 278679
Approved by: maintainer timeout (3+ weeks)