Cannot change TLS minimum version to 1.3 for internal encryption (between Ingress to Activator)

[izabelacg]

Describe the feature

I attempted to change the minimum TLS version (from 1.2 to 1.3) in the activator when internal encryption is activated, but kourier-tls tests failed (PR attempt #13930). They failed when this line is changed (communication between Ingress to Activator):

serving/cmd/activator/main.go

Line 288 in d07bf78

MinVersion: tls.VersionTLS12,

TLS 1.3 comes with numerous enhancements, such as a quicker TLS handshake and more secure cipher suites. We should aim to move minimum version from 1.2 to 1.3.

[KauzClay]

For visibility, the internal-encryption feature is undergoing some changes. One of them being the switch from internal-encryption to dataplane-trust config flags, see knative/networking#778.

We may want to consider this issue as the internal encryption track moves forward