fix: Add peer dependency support for react/react-dom 17 (#310)

Been testing it out for a bit and seems to work well so far.

Author: bcomnes

package.json

@@ -109,8 +109,8 @@
     "watch": "^1.0.2"
   },
   "peerDependencies": {
-    "react": "15.x || 16.x",
-    "react-dom": "15.x || 16.x"
+    "react": "15.x || 16.x || 17.x",
+    "react-dom": "15.x || 16.x || 17.x"
   },
   "dependencies": {
     "@babel/runtime": "^7.5.5",