chore(generic): enable coveralls

ci/script.sh

@@ -5,5 +5,7 @@ if [[ "$TRAVIS_OS_NAME" = "linux" ]]; then
     sudo docker run -it electron-forge-ci ci/docker.sh $NODE_INSTALLER
 else
     if [[ "$NODE_INSTALLER" = "yarn" ]]; then npm i -g yarn; fi
-    npm run test -- --installer=$NODE_INSTALLER
+    npm run test-coverage -- --installer=$NODE_INSTALLER
+    # Only publish coverage on the macOS yarn agent
+    if [[ "$NODE_INSTALLER" = "yarn" ]]; then cat coverage/lcov.info | node node_modules/coveralls/bin/coveralls.js; fi
 fi

package.json

@@ -39,6 +39,7 @@
     "babel-preset-es2015": "^6.16.0",
     "chai": "^3.5.0",
     "commitizen": "^2.8.6",
+    "coveralls": "^2.11.15",
     "cross-env": "^3.1.3",
     "cz-customizable": "4.0.0",
     "esdoc": "^0.5.1",