drop the node-status-code dependency

It was useful pre-v4, but now we're up to date.

index.js

@@ -14,7 +14,6 @@ const lowercaseKeys = require('lowercase-keys');
 const isRedirect = require('is-redirect');
 const unzipResponse = require('unzip-response');
 const createErrorClass = require('create-error-class');
-const nodeStatusCodes = require('node-status-codes');
 const isRetryAllowed = require('is-retry-allowed');
 const pkg = require('./package');
 
@@ -346,21 +345,21 @@ got.ReadError = createErrorClass('ReadError', stdError);
 got.ParseError = createErrorClass('ParseError', function (e, statusCode, opts, data) {
 	stdError.call(this, e, opts);
 	this.statusCode = statusCode;
-	this.statusMessage = nodeStatusCodes[this.statusCode];
+	this.statusMessage = http.STATUS_CODES[this.statusCode];
 	this.message = `${e.message} in "${urlLib.format(opts)}": \n${data.slice(0, 77)}...`;
 });
 
 got.HTTPError = createErrorClass('HTTPError', function (statusCode, opts) {
 	stdError.call(this, {}, opts);
 	this.statusCode = statusCode;
-	this.statusMessage = nodeStatusCodes[this.statusCode];
+	this.statusMessage = http.STATUS_CODES[this.statusCode];
 	this.message = `Response code ${this.statusCode} (${this.statusMessage})`;
 });
 
 got.MaxRedirectsError = createErrorClass('MaxRedirectsError', function (statusCode, opts) {
 	stdError.call(this, {}, opts);
 	this.statusCode = statusCode;
-	this.statusMessage = nodeStatusCodes[this.statusCode];
+	this.statusMessage = http.STATUS_CODES[this.statusCode];
 	this.message = 'Redirected 10 times. Aborting.';
 });
 

package.json

@@ -52,7 +52,6 @@
     "is-retry-allowed": "^1.0.0",
     "is-stream": "^1.0.0",
     "lowercase-keys": "^1.0.0",
-    "node-status-codes": "^2.0.0",
     "timed-out": "^3.0.0",
     "unzip-response": "^2.0.1",
     "url-parse-lax": "^1.0.0"