fix: declare babel-eslint as peer dependency

Author: ylemkimon

package.json

@@ -48,6 +48,7 @@
   "main": "./dist/index.js",
   "name": "eslint-plugin-flowtype",
   "peerDependencies": {
+    "babel-eslint": "*",
     "eslint": "^7.1.0"
   },
   "repository": {