chore: Set peerDeps to 4.x & drop Node 4

Author: joshwiens

package.json

@@ -4,14 +4,20 @@
   "author": "Tobias Koppers @sokra",
   "license": "MIT",
   "description": "css loader module for webpack",
-  "engines": {
-    "node": ">=0.12.0 || >= 4.3.0 < 5.0.0 || >=5.10"
-  },
   "files": [
     "lib",
     "index.js",
     "locals.js"
   ],
+  "scripts": {
+    "test": "mocha",
+    "test:cover": "npm run cover -- --report lcovonly",
+    "lint": "eslint lib test",
+    "travis:test": "npm run cover",
+    "travis:lint": "npm run lint",
+    "cover": "istanbul cover node_modules/mocha/bin/_mocha",
+    "release": "yarn run standard-version"
+  },
   "dependencies": {
     "babel-code-frame": "^6.26.0",
     "css-selector-tokenizer": "^0.7.0",
@@ -36,14 +42,15 @@
     "should": "^11.1.2",
     "standard-version": "^4.0.0"
   },
-  "scripts": {
-    "lint": "eslint lib test",
-    "test": "mocha",
-    "cover": "istanbul cover node_modules/mocha/bin/_mocha",
-    "test:cover": "npm run cover -- --report lcovonly",
-    "travis:test": "npm run cover",
-    "travis:lint": "npm run lint",
-    "release": "standard-version"
+  "peerDependencies": {
+    "webpack": "^3.0.0 || ^4.0.0-alpha.0 || ^4.0.0"
+  },
+  "engines": {
+    "node": ">= 6 || >= 8"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git@github.com:webpack/css-loader.git"
   },
   "homepage": "https://github.com/webpack-contrib/css-loader",
   "repository": "https://github.com/webpack-contrib/css-loader.git",