Add a missing peer dependency

package.json

@@ -52,6 +52,7 @@
     "electron-connect": "^0.6.1",
     "eslint": "^3.19.0",
     "eslint-plugin-react": "^7.0.0",
+    "file-loader": "^1.1.6",
     "mocha": "^5.0.0",
     "mocha-circleci-reporter": "0.0.2",
     "npm-run-all": "^4.1.2",

yarn.lock

@@ -2337,6 +2337,13 @@ file-entry-cache@^2.0.0:
     flat-cache "^1.2.1"
     object-assign "^4.0.1"
 
+file-loader@^1.1.6:
+  version "1.1.6"
+  resolved "https://registry.yarnpkg.com/file-loader/-/file-loader-1.1.6.tgz#7b9a8f2c58f00a77fddf49e940f7ac978a3ea0e8"
+  dependencies:
+    loader-utils "^1.0.2"
+    schema-utils "^0.3.0"
+
 filename-regex@^2.0.0:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/filename-regex/-/filename-regex-2.0.1.tgz#c1c4b9bee3e09725ddb106b75c1e301fe2f18b26"