feat: update webpack dependency range to allow installing webpack 5 beta

fixes #1504

Author: GaryB432

package.json

@@ -61,7 +61,7 @@
     "util.promisify": "1.0.0"
   },
   "peerDependencies": {
-    "webpack": ">=4.0.0 < 6.0.0"
+    "webpack": "^4.0.0 || ^5.0.0"
   },
   "keywords": [
     "webpack",