Nornir-pyntc

* Updated `pyntc` dependency to 2.0.0, which contains updates related to changes in netmiko 4.0. In short `delay_factor` was deprecated in favor of `read_timeout`.
* Dropped support for python3.7

New Contributors
* pszulczewski made their first contribution in https://github.com/networktocode/nornir-pyntc/pull/35

**Full Changelog**: https://github.com/networktocode/nornir-pyntc/compare/v2.0.0...v3.0.0

What's Changed

Added

- Add `wait_for_reload` kwarg in `pyntc_reboot` task to mirror updated pyntc methods as of `1.0.0` of pyntc.

Fixed

- `pyntc_config` - Update docstrings and support both list|str inputs.

Deprecated

- Remove `pyntc_show_list` tasks, as `pyntc_show` now accepts a list or a str argument.
- Remove `timer` argument from `pyntc_reboot` task as it was deprecated in underlying `pyntc` library in `1.0.0`.

**Full Changelog**: https://github.com/networktocode/nornir-pyntc/compare/v1.0.0...v1.0.1

- Initial release