feat: return source map object

Author: eddyerburgh

Diff for: lib/process.js

@@ -1,5 +1,4 @@
 const vueCompiler = require('vue-template-compiler')
-const convertSourceMap = require('convert-source-map')
 const compileTemplate = require('./template-compiler')
 const generateSourceMap = require('./generate-source-map')
 const addTemplateMapping = require('./add-template-mapping')
@@ -74,9 +73,5 @@ module.exports = function (src, path) {
     }
   }
 
-  if (map) {
-    output += '\n' + convertSourceMap.fromJSON(map.toString()).toComment()
-  }
-
-  return output
+  return { code: output, map }
 }