workflow: add script to unit tests coverage.

Author: gchoqueux

package.json

@@ -11,6 +11,7 @@
     "test-unit": "npm run base-test-unit test/unit",
     "test-functional": "mocha -t 60000 --require test/hooks_functional.js --recursive test/functional",
     "test-with-coverage": "nyc -n src -r html cross-env npm run test-unit",
+    "test-with-coverage_lcov": "nyc -n src --reporter=lcov cross-env npm run test-unit",
     "base-test-unit": "cross-env BABEL_DISABLE_CACHE=1 mocha --require @babel/register --file test/unit/bootstrap.js",
     "build": "cross-env NODE_ENV=production webpack",
     "transpile": "cross-env BABEL_DISABLE_CACHE=1 babel src --out-dir lib",