Update to Webpack 4

Author: philwareham

dist/four-point-seven/manifest.json

@@ -5,4 +5,4 @@
   "description": "The default theme shipped with Textpattern CMS 4.7.",
   "author": "Team Textpattern",
   "author_uri": "https://github.com/textpattern/textpattern-default-theme"
-}
+}

dist/four-point-seven/styles/default.css

@@ -1595,3 +1595,4 @@ nav ol::after,
     page-break-inside: avoid;
   }
 }
+