Add 'prepare' script per husky docs (#789)

https://blog.typicode.com/husky-git-hooks-autoinstall/

Author: tjlav5

package.json

@@ -85,7 +85,8 @@
     "lint": "prettier --check . && eslint 'src/**/*.{ts,tsx}'",
     "lint:fix": "eslint --fix 'src/**/*.{ts,tsx}' && npm run format",
     "fmt": "npm run format",
-    "format": "prettier --write ."
+    "format": "prettier --write .",
+    "prepare": "husky install"
   },
   "eslintConfig": {
     "extends": [