Upgrading server dependancies (#4566)

vendor/github.com/rsc/letsencrypt/lets.go

@@ -8,6 +8,30 @@
 // that can prove control over the given domain's DNS records or
 // the servers pointed at by those records.
 //
+// Warning
+//
+// Like any other random code you find on the internet, this package should
+// not be relied upon in important, production systems without thorough testing
+// to ensure that it meets your needs.
+//
+// In the long term you should be using
+// https://golang.org/x/crypto/acme/autocert instead of this package.
+// Send improvements there, not here.
+//
+// This is a package that I wrote for my own personal web sites (swtch.com, rsc.io)
+// in a hurry when my paid-for SSL certificate was expiring. It has no tests,
+// has barely been used, and there is some anecdotal evidence that it does
+// not properly renew certificates in a timely fashion, so servers that run for
+// more than 3 months may run into trouble.
+// I don't run this code anymore: to simplify maintenance, I moved the sites
+// off of Ubuntu VMs and onto Google App Engine, configured with inexpensive
+// long-term certificates purchased from cheapsslsecurity.com.
+//
+// This package was interesting primarily as an example of how simple the API
+// for using LetsEncrypt.org could be made, in contrast to the low-level
+// implementations that existed at the time. In that respect, it helped inform
+// the design of the golang.org/x/crypto/acme/autocert package.
+//
 // Quick Start
 //
 // A complete HTTP/HTTPS web server using TLS certificates from LetsEncrypt.org,