update react and react-dom peer deps to be >=15.0.0

Author: madhums

package.json

@@ -8,8 +8,8 @@
     "url": "git+https://github.com/flyingant/react-scroll-to-component-ssr.git"
   },
   "peerDependencies": {
-    "react": "^0.14.0 || ^15.0.0 || ^16.0.0",
-    "react-dom": "^0.14.0 || ^15.0.0 || ^16.0.0"
+    "react": ">=15.0.0",
+    "react-dom": ">=15.0.0"
   },
   "dependencies": {
     "ssr-scroll-to": "0.0.2"