chore: add keywords per by eslint.org

eslint.org recommends adding eslint, eslintplugin, and eslint-plugin keywords to plugin npm packages.

Author: JasonWeinzierl

package.json

@@ -18,6 +18,8 @@
     "lint",
     "rules",
     "eslint",
+    "eslintplugin",
+    "eslint-plugin",
     "rxjs"
   ],
   "sideEffects": false,