Merge pull request #23 from github/publish-to-gpr-as-well

Publish to GPR as a postpublish step

Author: koddsson

package.json

@@ -17,7 +17,8 @@
     "build": "npm run build-umd && npm run build-esm && cp index.js.flow dist/index.umd.js.flow && cp index.js.flow dist/index.esm.js.flow",
     "pretest": "npm run build",
     "prepublishOnly": "npm run build",
-    "test": "karma start test/karma.config.js"
+    "test": "karma start test/karma.config.js",
+    "postpublish": "npm publish --ignore-scripts --@github:registry='https://npm.pkg.github.com'"
   },
   "keywords": [
     "crop",