Update mock-fs so node 10 tests work
MODIFY
package.json
package.json
"finalhandler": "^1.1.1",
"gulp": "^3.9.0",
"mocha": "^5.1.1",
- "mock-fs": "^4.4.2",
+ "mock-fs": "^4.5.0",
"pre-commit": "^1.1.3",
"serve-static": "^1.13.1",
"sinon": "^4.5.0"

Update mock-fs so node 10 tests work