Update file-loader requirement from ^3.0.1 to ^4.0.0 (#1086)

Updates the requirements on [file-loader](https://github.com/webpack-contrib/file-loader) to permit the latest version.
- [Release notes](https://github.com/webpack-contrib/file-loader/releases)
- [Changelog](https://github.com/webpack-contrib/file-loader/blob/master/CHANGELOG.md)
- [Commits](https://github.com/webpack-contrib/file-loader/compare/v3.0.1...v4.0.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

package.json

@@ -66,7 +66,7 @@
 		"eslint-plugin-standard": "^3.1.0",
 		"eslint-plugin-vue": "^4.5.0",
 		"extract-text-webpack-plugin": "^3.0.2",
-		"file-loader": "^3.0.1",
+		"file-loader": "^4.0.0",
 		"jest": "^24.0.0",
 		"jest-serializer-vue": "^2.0.2",
 		"mini-css-extract-plugin": "^0.7.0",