remove peerDep on @vue/compiler-sfc and use custom check instead

Author: yyx990803

Diff for: package.json

@@ -28,9 +28,6 @@
       "git add"
     ]
   },
-  "peerDependencies": {
-    "@vue/compiler-sfc": "^3.0.0-alpha.0"
-  },
   "dependencies": {
     "chalk": "^3.0.0",
     "hash-sum": "^2.0.0",

Diff for: src/index.ts

@@ -1,3 +1,12 @@
+try {
+  require.resolve('@vue/compiler-sfc')
+} catch (e) {
+  throw new Error(
+    'vue-loader requires @vue/compiler-sfc to be present in the dependency ' +
+      'tree.'
+  )
+}
+
 import * as webpack from 'webpack'
 import path from 'path'
 import qs from 'querystring'