Bump js-yaml and gulp-svgmin

Removes [js-yaml](https://github.com/nodeca/js-yaml). It's no longer used after updating ancestor dependency [gulp-svgmin](https://github.com/ben-eb/gulp-svgmin). These dependencies need to be updated together.


Removes `js-yaml`

Updates `gulp-svgmin` from 3.0.0 to 4.1.0
- [Release notes](https://github.com/ben-eb/gulp-svgmin/releases)
- [Changelog](https://github.com/ben-eb/gulp-svgmin/blob/master/CHANGELOG.md)
- [Commits](ben-eb/gulp-svgmin@v3.0.0...v4.1.0)

---
updated-dependencies:
- dependency-name: js-yaml
  dependency-version: 
  dependency-type: indirect
- dependency-name: gulp-svgmin
  dependency-version: 4.1.0
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]