set ClientAuth and ClientCAs on plugin client tls config

client.go

@@ -574,6 +574,8 @@ func (c *Client) Start() (addr net.Addr, err error) {
 
 		c.config.TLSConfig = &tls.Config{
 			Certificates: []tls.Certificate{cert},
+			ClientAuth:   tls.RequireAndVerifyClientCert,
+			MinVersion:   tls.VersionTLS12,
 			ServerName:   "localhost",
 		}
 	}
@@ -774,7 +776,7 @@ func (c *Client) Start() (addr net.Addr, err error) {
 }
 
 // loadServerCert is used by AutoMTLS to read an x.509 cert returned by the
-// server, and load it as the RootCA for the client TLSConfig.
+// server, and load it as the RootCA and ClientCA for the client TLSConfig.
 func (c *Client) loadServerCert(cert string) error {
 	certPool := x509.NewCertPool()
 
@@ -791,6 +793,7 @@ func (c *Client) loadServerCert(cert string) error {
 	certPool.AddCert(x509Cert)
 
 	c.config.TLSConfig.RootCAs = certPool
+	c.config.TLSConfig.ClientCAs = certPool
 	return nil
 }