housekeeping: npm audit resolutions (via #5457)

* add `security-audit` script

* npm audit fix

* remove nyc

* nightwatch@1

this breaks the test suite, but it appears to have already regressed. leaving it for another day, TODO: open a backlog ticket

* add `security-audit` script

* disable mocha exclusivity

* update package-lock.json

* cypress@3.4.0

* `npm audit fix`

* @release-it/conventional-changelog@1.1.0

* release-it@12

docs/development/scripts.md

@@ -19,6 +19,7 @@ Script name | Description
 `build-bundle` | Build `swagger-ui-bundle.js` only.
 `build-core` | Build `swagger-ui.(js\|css)` only.
 `build-standalone` | Build `swagger-ui-standalone-preset.js` only.
+`build-stylesheets` | Build `swagger-ui.css` only.
 
 ### Testing
 Script name | Description
@@ -26,5 +27,4 @@ Script name | Description
 `test` | Run unit tests in Node and run ESLint in errors-only mode.
 `just-test` | Run unit tests in the browser with Karma.
 `just-test-in-node` | Run unit tests in Node.
-`just-check-coverage` | Generate a code coverage report with NYC.
 `e2e` | Run end-to-end tests (requires JDK and Selenium).