feat(react): upgrade to react-scripts@2 (#300)

- Update to `react-scripts@2`
- Update React version
- Update React DOM version
- Add `browserslist` for `react-scripts@2`
- Downgrade ESLint to 5.6.0 as a requirement to `react-scripts@2`

Author: francoischalifour

scripts/__snapshots__/e2e-templates.test.js.snap

@@ -3688,6 +3688,12 @@ exports[`Templates React InstantSearch File content: package.json 1`] = `
     \\"lint\\": \\"eslint .\\",
     \\"lint:fix\\": \\"npm run lint -- --fix\\"
   },
+  \\"browserslist\\": [
+    \\">0.2%\\",
+    \\"not dead\\",
+    \\"not ie <= 11\\",
+    \\"not op_mini all\\"
+  ],
   \\"partialDependencies\\": {
     \\"react-instantsearch-dom\\": \\"1.0.0\\"
   }

src/templates/React InstantSearch/package.json

@@ -10,19 +10,25 @@
   },
   "dependencies": {
     "algoliasearch": "3.30.0",
-    "react": "16.5.2",
-    "react-dom": "16.5.2",
+    "react": "16.6.0",
+    "react-dom": "16.6.0",
     "react-instantsearch-dom": "{{libraryVersion}}",
-    "react-scripts": "1.1.5"
+    "react-scripts": "2.0.5"
   },
   "devDependencies": {
-    "eslint": "5.7.0",
+    "eslint": "5.6.0",
     "eslint-config-algolia": "13.2.3",
     "eslint-config-prettier": "3.1.0",
     "eslint-plugin-import": "2.14.0",
     "eslint-plugin-prettier": "3.0.0",
     "eslint-plugin-react": "7.11.1",
     "prettier": "1.14.3",
     "prop-types": "15.6.2"
-  }
+  },
+  "browserslist": [
+    ">0.2%",
+    "not dead",
+    "not ie <= 11",
+    "not op_mini all"
+  ]
 }