Updates the requirements on [xema](https://github.com/hrzndhrn/xema) to permit the latest version.
- [Release notes](https://github.com/hrzndhrn/xema/releases)
- [Changelog](https://github.com/hrzndhrn/xema/blob/master/CHANGELOG.md)
- [Commits](https://github.com/hrzndhrn/xema/commits/v0.13.7)

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

• Commit 4d6585e
• #114: build(deps): update xema requirement from 0.13.6 to 0.13.7
• Branch master

dependabot-preview[bot] authored GitHub committed