fix(elm-asset-webpack-loader): dependency instead of dev dependency

elm-asset-webpack-loader has to be available on execution time (from the perspective of
create-elm-app)

Closes #382

Author: andys8

package.json

@@ -36,6 +36,7 @@
     "css-loader": "^3.2.0",
     "dotenv": "^5.0.0",
     "elm": "latest-0.19.1",
+    "elm-asset-webpack-loader": "1.1.1",
     "elm-hot-webpack-loader": "^1.1.5",
     "elm-test": "latest-0.19.1",
     "elm-webpack-loader": "6.0.0",
@@ -71,7 +72,6 @@
     "cross-env": "^5.2.0",
     "cz-conventional-changelog": "^3.0.2",
     "dir-compare": "^1.4.0",
-    "elm-asset-webpack-loader": "1.1.1",
     "eslint": "^6.1.0",
     "eslint-plugin-prettier": "^3.1.0",
     "husky": "^3.0.3",