Bump cfssl to 56268a6

vendor/github.com/cloudflare/cfssl/api/client/client.go

@@ -105,14 +105,28 @@ func (srv *server) getURL(endpoint string) string {
 	return fmt.Sprintf("%s/api/v1/cfssl/%s", srv.URL, endpoint)
 }
 
-func (srv *server) createTransport() (transport *http.Transport) {
-	transport = new(http.Transport)
+func (srv *server) createTransport() *http.Transport {
+	// Start with defaults from http.DefaultTransport
+	transport := &http.Transport{
+		Proxy: http.ProxyFromEnvironment,
+		DialContext: (&net.Dialer{
+			Timeout:   30 * time.Second,
+			KeepAlive: 30 * time.Second,
+			DualStack: true,
+		}).DialContext,
+		MaxIdleConns:          100,
+		IdleConnTimeout:       90 * time.Second,
+		TLSHandshakeTimeout:   10 * time.Second,
+		ExpectContinueTimeout: 1 * time.Second,
+	}
 	// Setup HTTPS client
 	tlsConfig := srv.TLSConfig
 	tlsConfig.BuildNameToCertificate()
 	transport.TLSClientConfig = tlsConfig
 	// Setup Proxy
-	transport.Proxy = srv.proxy
+	if srv.proxy != nil {
+		transport.Proxy = srv.proxy
+	}
 	return transport
 }