Bump karma-viewport from 1.0.2 to 1.0.3 in /build

Bumps [karma-viewport](https://github.com/squidfunk/karma-viewport) from 1.0.2 to 1.0.3.
- [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/1.0.2...1.0.3

)

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