Adding arista port-channel support

[RobelK1]

I deleted the prevuous two commits I did and pushed a brand new commit that fixed the sign-off and unittests as per @pmazzini comment

[codecov[bot]]

Codecov Report

Patch and project coverage have no change.

Comparison is base (74ae03f) 72.77% compared to head (ef9cfd8) 72.77%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #501 +/- ## ======================================= Coverage 72.77% 72.77% ======================================= Files 90 90 Lines 5742 5742 ======================================= Hits 4179 4179 Misses 1391 1391 Partials 172 172 ``` | [Impacted Files](https://codecov.io/gh/insomniacslk/dhcp/pull/501?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=insomniac) | Coverage Δ | | |---|---|---| | [dhcpv4/ztpv4/parse\_circuitid.go](https://codecov.io/gh/insomniacslk/dhcp/pull/501?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=insomniac#diff-ZGhjcHY0L3p0cHY0L3BhcnNlX2NpcmN1aXRpZC5nbw==) | `85.00% <ø> (ø)` | | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=insomniac). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=insomniac)

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