Update dependency @types/prop-types to v15.7.4

Author: renovate-bot

package.json

@@ -49,7 +49,7 @@
     "@types/jest": "26.0.21",
     "@types/node-sass": "4.11.1",
     "@types/prettier": "2.2.3",
-    "@types/prop-types": "15.7.3",
+    "@types/prop-types": "15.7.4",
     "@types/react": "17.0.3",
     "@types/react-bootstrap": "1.0.1",
     "@types/react-dom": "17.0.2",