Support for previous commit. Add npm script for running danger to pac…

…kage.json.

package.json

@@ -35,6 +35,7 @@
     "bundle": "npm run format:write && npm run package",
     "ci-test": "npx jest",
     "coverage": "npx make-coverage-badge --output-path ./badges/coverage.svg",
+    "danger": "npx danger ci",
     "format:write": "npx prettier --write .",
     "format:check": "npx prettier --check .",
     "lint": "npx eslint . -c ./.github/linters/.eslintrc.yml",