chore(npm): add peerDependencies >= 5.1.0 textlint

Author: azu

package.json

@@ -45,5 +45,8 @@
     "sorted-joyo-kanji": "^0.2.0",
     "textlint-rule-helper": "^1.1.3",
     "textlint-rule-prh": "^2.0.0"
+  },
+  "peerDependencies": {
+    "textlint": ">= 5.1.0"
   }
 }