Bump karma-viewport from 1.0.5 to 1.0.6 in /build

Bumps [karma-viewport](https://github.com/squidfunk/karma-viewport) from 1.0.5 to 1.0.6.
- [Release notes](https://github.com/squidfunk/karma-viewport/releases)
- [Changelog](https://github.com/squidfunk/karma-viewport/blob/master/CHANGELOG)
- [Commits](https://github.com/squidfunk/karma-viewport/compare/1.0.5...1.0.6

)

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