feat: Script source map support in assemble (#74)

* feat: Script source map support in assemble

* fix: Handle closing tags in script code

Author: znck

package.json

@@ -57,6 +57,7 @@
     "@vue/component-compiler-utils": "^1.2.1",
     "clean-css": "^4.1.11",
     "hash-sum": "^1.0.2",
-    "postcss-modules-sync": "^1.0.0"
+    "postcss-modules-sync": "^1.0.0",
+    "source-map": "0.6.*"
   }
 }