fix: log deprecation message once, with stack

Author: gr2m

lib/http-error.js

@@ -1,3 +1,6 @@
+const Deprecation = require('deprecation')
+const logOnce = require('once')(deprecation => console.warn(deprecation))
+
 module.exports = class HttpError extends Error {
   constructor (message, statusCode, headers, request) {
     super(message)
@@ -12,7 +15,7 @@ module.exports = class HttpError extends Error {
     this.status = statusCode
     Object.defineProperty(this, 'code', {
       get () {
-        console.warn('`error.code` is deprecated, use `error.status`.')
+        logOnce(new Deprecation('[@octokit/request] `error.code` is deprecated, use `error.status`.'))
         return statusCode
       }
     })