Add changelog to package

Author: Niilo Keinänen

package.json

@@ -56,6 +56,7 @@
     "lib/helpers.js",
     "lib/helpers.d.ts",
     "lib/index.js",
-    "lib/index.d.ts"
+    "lib/index.d.ts",
+    "CHANGELOG.md"
   ]
 }