Bump activesupport from 4.2.1 to 6.0.0

Bumps [activesupport](https://github.com/rails/rails) from 4.2.1 to 6.0.0.
- [Release notes](https://github.com/rails/rails/releases)
- [Changelog](https://github.com/rails/rails/blob/v6.0.0/activesupport/CHANGELOG.md)
- [Commits](rails/rails@v4.2.1...v6.0.0)

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

dependabot committed Oct 3, 2019

e1c9719