fix(gatsby-react-router-scroll): add missing dependency prop-types

Author: merceyz

packages/gatsby-react-router-scroll/package.json

@@ -7,7 +7,8 @@
     "url": "https://github.com/gatsbyjs/gatsby/issues"
   },
   "dependencies": {
-    "@babel/runtime": "^7.15.4"
+    "@babel/runtime": "^7.15.4",
+    "prop-types": "^15.7.2"
   },
   "devDependencies": {
     "@babel/cli": "^7.15.4",