chore: --detectOpenHandles is node 8+

Author: shellscape

package.json

@@ -21,9 +21,9 @@
     "release:ci": "conventional-github-releaser -p angular",
     "release:validate": "commitlint --from=$(git describe --tags --abbrev=0) --to=$(git rev-parse HEAD)",
     "security": "nsp check",
-    "test": "jest --detectOpenHandles",
+    "test": "jest",
     "test:watch": "jest --watch",
-    "test:coverage": "jest --collectCoverageFrom='lib/**/*.js' --coverage --detectOpenHandles",
+    "test:coverage": "jest --collectCoverageFrom='lib/**/*.js' --coverage",
     "ci:lint": "npm run lint && npm run security",
     "ci:test": "npm run test -- --runInBand",
     "ci:coverage": "npm run test:coverage -- --runInBand",