Fix ESLint airbnb/react-app conflict

- Give up code style linting in favor of CRA's linting
methods. For the cause visit
(facebook/create-react-app#3540)

client/.eslintrc

@@ -1,7 +1,6 @@
 {
   "parser": "babel-eslint",
   "extends": [
-    "airbnb",
     "plugin:react/recommended",
     "plugin:jest/recommended",
     "react-app"

client/package.json

@@ -3,6 +3,7 @@
   "version": "0.1.0",
   "private": true,
   "dependencies": {
+    "ajv": "^6.5.3",
     "prop-types": "^15.6.2",
     "ramda": "^0.25.0",
     "react": "^16.4.2",
@@ -24,17 +25,16 @@
     "lint": "eslint ."
   },
   "devDependencies": {
-    "babel-eslint": "^9.0.0",
+    "babel-eslint": "^7.2.3",
     "babel-plugin-module-resolver": "^3.1.1",
     "enzyme": "^3.5.0",
     "enzyme-adapter-react-16": "^1.3.1",
-    "eslint": "^5.5.0",
-    "eslint-config-airbnb": "^17.1.0",
+    "eslint": "^4.19.1",
     "eslint-config-react-app": "^2.1.0",
     "eslint-import-resolver-babel-module": "^4.0.0",
     "eslint-plugin-import": "^2.14.0",
     "eslint-plugin-jest": "^21.22.0",
-    "eslint-plugin-jsx-a11y": "^6.1.1",
+    "eslint-plugin-jsx-a11y": "^5.1.1",
     "eslint-plugin-react": "^7.11.1",
     "react-fake-props": "^0.2.1"
   }