Adjust minimum scapy version to 2.6.1

[epenet]

Proposed change

Follow-up to #129327, now that v2.6.1 has been released.

See https://github.com/secdev/scapy/releases/tag/v2.6.1
In particular: secdev/scapy#4558

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• Dependency upgrade
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• Breaking change (fix/feature causing existing functionality to break)
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• This PR fixes or closes issue: fixes #
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[home-assistant]

Hey there @bdraco, mind taking a look at this pull request as it has been labeled with an integration (dhcp) you are listed as a code owner for? Thanks!

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