Change minimum TLS version to 1.3 for internal encryption (between ac…

…tivator and queue-proxy) (#13887)

* change mininum TLS version for when internal encryption is activated

* revert tls1.3 for activator - main.go

pkg/activator/certificate/cache.go

@@ -103,7 +103,7 @@ func (cr *CertCache) updateCache(secret *corev1.Secret) {
 
 	cr.TLSConf.RootCAs = pool
 	cr.TLSConf.ServerName = certificates.LegacyFakeDnsName
-	cr.TLSConf.MinVersion = tls.VersionTLS12
+	cr.TLSConf.MinVersion = tls.VersionTLS13
 }
 
 func (cr *CertCache) handleCertificateUpdate(_, new interface{}) {