Manually add acorn as dependency

Signed-off-by: Julius Härtl <jus@bitgrid.net>

package.json

@@ -57,6 +57,7 @@
 		"@babel/plugin-syntax-dynamic-import": "^7.2.0",
 		"@babel/preset-env": "^7.2.3",
 		"@vue/test-utils": "^1.0.0-beta.28",
+		"acorn": "^6.0.5",
 		"babel-eslint": "^10.0.1",
 		"babel-jest": "^23.6.0",
 		"babel-loader": "^8.0.5",
@@ -70,11 +71,9 @@
 		"eslint-plugin-promise": "^4.0.1",
 		"eslint-plugin-standard": "^4.0.0",
 		"eslint-plugin-vue": "^5.1.0",
-		"extract-text-webpack-plugin": "^3.0.2",
 		"file-loader": "^3.0.1",
 		"jest": "^23.6.0",
 		"jest-serializer-vue": "^2.0.2",
-		"mini-css-extract-plugin": "^0.5.0",
 		"node-sass": "^4.11.0",
 		"prettier-eslint": "^8.8.2",
 		"raw-loader": "^1.0.0",