Fixes README and missing docs in published package

Author: dotansimha

.changeset/silent-lemons-travel.md

@@ -0,0 +1,5 @@
+---
+'@graphql-eslint/eslint-plugin': patch
+---
+
+Fixes README and missing docs in published package

package.json

@@ -11,6 +11,7 @@
     "lint": "eslint --config .eslintrc.json --ext .ts .",
     "prebuild": "rimraf packages/*/dist",
     "build": "tsc --project tsconfig.json && bob build",
+    "postbuild": "cp -r README.md docs ./packages/plugin/dist/",
     "test": "jest",
     "prerelease": "yarn build",
     "release": "changeset publish",