use go1.11 with go mod

vendor/github.com/gin-gonic/autotls/autotls.go

@@ -1,24 +0,0 @@
-package autotls
-
-import (
-	"crypto/tls"
-	"net/http"
-
-	"golang.org/x/crypto/acme/autocert"
-)
-
-// Run support 1-line LetsEncrypt HTTPS servers
-func Run(r http.Handler, domain ...string) error {
-	return http.Serve(autocert.NewListener(domain...), r)
-}
-
-// RunWithManager support custom autocert manager
-func RunWithManager(r http.Handler, m *autocert.Manager) error {
-	s := &http.Server{
-		Addr:      ":https",
-		TLSConfig: &tls.Config{GetCertificate: m.GetCertificate},
-		Handler:   r,
-	}
-
-	return s.ListenAndServeTLS("", "")
-}