Update to microbundle v0.8.3

Fixes #20.

Author: jviide

package.json

@@ -53,7 +53,7 @@
     "eslint": "^5.2.0",
     "eslint-config-developit": "^1.1.1",
     "jest": "^23.4.2",
-    "microbundle": "^0.7.0",
+    "microbundle": "^0.8.3",
     "preact": "^8.2.9"
   },
   "dependencies": {}