Two security vulnerabilities for dev dependencies founded

[jianliao]

Expected Behavior

No security vulnerabilities

Actual Behavior

Found 2 vulnerabilities (1 low, 1 moderate)

Reproduce Scenario (including but not limited to)

Steps to Reproduce

npm audit

Browser name/version/os (ie Chrome Version 62.0.3202.94 (Official Build) (64-bit) MacOS)

Spectrum-CSS version

master

Sample Code that illustrates the problem

Screenshots (if applicable)

[jianliao]

I think we don't use gulp-watch any more. It should be removed. All current watch functionality comes from gulp 4.0.0.