chore(package): update http-server to version 0.12.3

Closes #8

Author: greenkeeper[bot]

package.json

@@ -21,7 +21,7 @@
     "babelify": "^7.3.0",
     "chai": "^4.0.2",
     "gl": "^4.0.2",
-    "http-server": "^0.10.0",
+    "http-server": "^0.12.3",
     "mocha": "^3.2.0",
     "pngjs": "^3.0.0"
   },