feat: support tls for etcd client (#1390)

* feat: support tls for etcd client

* chore: fix typo

* refactor: rename TrustedCAFile to CACertFile

* docs: add comments

* fix: missing tls registration

* feat: add InsecureSkipVerify config for testing

core/discov/accountregistry.go

@@ -6,3 +6,9 @@ import "github.com/tal-tech/go-zero/core/discov/internal"
 func RegisterAccount(endpoints []string, user, pass string) {
 	internal.AddAccount(endpoints, user, pass)
 }
+
+// RegisterTLS registers the CertFile/CertKeyFile/CACertFile to the given etcd.
+func RegisterTLS(endpoints []string, certFile, certKeyFile, caFile string,
+	insecureSkipVerify bool) error {
+	return internal.AddTLS(endpoints, certFile, certKeyFile, caFile, insecureSkipVerify)
+}