Move react to peerDependencies

https://github.com/facebook/prop-types#how-to-depend-on-this-package
facebook/prop-types#44

Author: aaronjensen

package.json

@@ -25,8 +25,7 @@
     "url": "https://github.com/bentaylor2/react-structured-data.git"
   },
   "dependencies": {
-    "prop-types": "^15.6.0",
-    "react": "^16.2.0"
+    "prop-types": "^15.6.0"
   },
   "devDependencies": {
     "autoprefixer": "7.1.6",
@@ -59,6 +58,9 @@
     "webpack-cli": "^3.0.2",
     "webpack-dev-server": "^3.1.4"
   },
+  "peerDependencies": {
+    "react": "^16.2.0"
+  },
   "scripts": {
     "start": "BABEL_ENV=development webpack-dev-server --mode development --open --hot",
     "build": "BABEL_ENV=production babel src/core --plugins transform-object-assign,transform-class-properties,transform-es2015-modules-commonjs --presets babel-preset-stage-2,babel-preset-react-app --out-dir dist"