fix: don't rely on plugin order

laravel mix always puts VueLoaderPlugin after any user-defined plugins,
so ident isn't set yet

fixes #49

Author: KaelWD

lib/plugin.js

@@ -1,5 +1,15 @@
 const RuleSet = require('webpack/lib/RuleSet')
 const progressiveLoaderModule = require('../progressive-loader/module')
+let vueLoaderPath
+try {
+  vueLoaderPath = require.resolve('vue-loader')
+} catch (err) {}
+
+function isVueLoader (use) {
+  return use.ident === 'vue-loader-options' ||
+    use.loader === 'vue-loader' ||
+    (vueLoaderPath && use.loader === vueLoaderPath)
+}
 
 class VuetifyLoaderPlugin {
   constructor (options) {
@@ -12,7 +22,7 @@ class VuetifyLoaderPlugin {
     const { rules } = new RuleSet(rawRules)
 
     // find the rule that applies to vue files
-    const vueRuleIndex = rules.findIndex(rule => rule.use && rule.use.find(u => u.ident === 'vue-loader-options'))
+    const vueRuleIndex = rules.findIndex(rule => rule.use && rule.use.find(isVueLoader))
     const vueRule = rules[vueRuleIndex]
 
     if (!vueRule) {
@@ -31,7 +41,7 @@ class VuetifyLoaderPlugin {
     })
 
     if (this.options.progressiveImages) {
-      const vueLoaderOptions = vueRule.use.find(use => use.ident === 'vue-loader-options').options
+      const vueLoaderOptions = vueRule.use.find(isVueLoader).options
       vueLoaderOptions.compilerOptions = vueLoaderOptions.compilerOptions || {}
       vueLoaderOptions.compilerOptions.modules = vueLoaderOptions.compilerOptions.modules || []
       vueLoaderOptions.compilerOptions.modules.push(progressiveLoaderModule)