fix: react-native-git-upgrade/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-INFLIGHT-6095116

Author: snyk-bot

react-native-git-upgrade/package.json

@@ -22,9 +22,9 @@
     "minimist": "^1.2.0",
     "npmlog": "^4.0.0",
     "promise": "^7.1.1",
-    "rimraf": "^2.5.4",
+    "rimraf": "^4.0.0",
     "semver": "^5.0.3",
     "shelljs": "^0.7.5",
-    "yeoman-environment": "1.5.3"
+    "yeoman-environment": "3.0.0"
   }
 }