Enhancement: Enforce Minimum TLS Version

[Hacks4Snacks]

The webhook server does not enforce a minimum TLS version of 1.2. TLS 1.0 and 1.1 are outdated and have known vulnerabilities.

[Hacks4Snacks]

If accepted I am more than happy to get a PR submitted.

[sshiba]

I have a requirement that requires the ability to enforce a minimum TLS version of 1.2 and it will benefit if this project is accepted.