Run happo-ci-github-actions via script

I couldn't get yarn to execute the bash script that
happo-ci-github-actions is. Going to try wrapping it in a scripts entry
to ensure bash is used.

package.json

@@ -7,6 +7,7 @@
     "lint": "eslint src/",
     "test": "jest",
     "happo": "happo",
+    "happo-ci-github-actions": "bash ./node_modules/.bin/happo-ci-github-actions",
     "build": "babel ./src --out-dir ./",
     "prepublishOnly": "yarn build",
     "dev": "storybook dev -p 9001 -c .storybook",