fix: support HtmlWebpackPlugin v4 hooks interface (#14)

Author: keithgabryelski

Diff for: index.js

@@ -23,6 +23,7 @@
 // https://github.com/ampedandwired/html-webpack-plugin#events
 
 'use strict'
+const HtmlWebpackPlugin = require('html-webpack-plugin')
 const escapeStringRegexp = require('escape-string-regexp')
 
 class InterpolateHtmlPlugin {
@@ -32,7 +33,7 @@ class InterpolateHtmlPlugin {
 
   apply(compiler) {
     compiler.hooks.compilation.tap('InterpolateHtmlPlugin', compilation => {
-      compilation.hooks.htmlWebpackPluginBeforeHtmlProcessing.tap(
+      HtmlWebpackPlugin.getHooks(compilation).afterTemplateExecution.tap(
         'InterpolateHtmlPlugin',
         data => {
           // Run HTML through a series of user-specified string replacements.

Diff for: package.json

@@ -33,6 +33,6 @@
     "escape-string-regexp": "^1.0.5"
   },
   "peerDependencies": {
-    "html-webpack-plugin": "^3.2.0"
+    "html-webpack-plugin": ">=4.5.1"
   }
 }