fix(package.json): Resolve react/react-dom dependency conflict for embedded users (#734)

* fix(package.json): Resolve react/react-dom dependency conflict for embedded users

Some of the recent changes around the script-tag support for ohif/Viewers included moving react and
react-dom from peerDependencies to dependencies. This caused an error for embedded consumers of the
viewer because there could be multiple versions of react included. The error in the console points
to this link: https://reactjs.org/warnings/invalid-hook-call-warning.html. These changes are
necessary to resolve the issue for embedded users and don't seem to break the standalone version
either.

* fix(script-tag/index.html): Add `react` and `react-dom` as external scripts for cypress tests

The cyrpress tests won't pass unless we add the `react` and `react-dom` dependencies as external
scripts since they're no longer first order depdencies.

cypress/support/script-tag/index.html

@@ -25,6 +25,10 @@
 
   <div id="root"></div>
 
+  <!-- Load React. -->
+  <script crossorigin src="https://unpkg.com/react@16/umd/react.production.min.js"></script>
+  <script crossorigin src="https://unpkg.com/react-dom@16/umd/react-dom.production.min.js"></script>
+
   <script src="/dist/index.umd.js" crossorigin></script>
   <script>
     window.config = {

package.json

@@ -72,6 +72,10 @@
       "path": "./node_modules/cz-conventional-changelog"
     }
   },
+  "peerDependencies": {
+    "react": "^16.8.6",
+    "react-dom": "^16.8.6"
+  },
   "dependencies": {
     "@babel/runtime": "^7.4.5",
     "@ohif/extension-cornerstone": "0.0.43",
@@ -97,8 +101,6 @@
     "ohif-core": "0.11.0",
     "oidc-client": "1.8.x",
     "prop-types": "^15.7.2",
-    "react": "^16.8.6",
-    "react-dom": "^16.8.6",
     "react-dropzone": "^10.1.5",
     "react-i18next": "^10.11.0",
     "react-redux": "^7.1.0",
@@ -144,6 +146,8 @@
     "lodash": "4.17.11",
     "lodash.clonedeep": "4.5.0",
     "prettier": "1.18.x",
+    "react": "^16.8.6",
+    "react-dom": "^16.8.6",
     "react-scripts": "^3.0.1",
     "rollup": "^1.15.5",
     "rollup-plugin-babel": "^4.3.2",

rollup.config.js

@@ -12,6 +12,11 @@ import builtins from 'rollup-plugin-node-builtins'
 import replace from 'rollup-plugin-replace';
 import serve from 'rollup-plugin-serve'
 
+const globals = {
+  react: 'React',
+  'react-dom': 'ReactDOM',
+};
+
 const startServer = process.env.START_SERVER === 'true';
 
 export default {
@@ -24,12 +29,14 @@ export default {
       exports: 'named',
       name: 'OHIFStandaloneViewer',
       esModule: false,
+      globals,
     },
     {
       file: pkg.module,
       format: 'es',
       exports: 'named',
       sourcemap: true,
+      globals,
     },
   ],
   plugins: [