Bump premailer from 3.6.1 to 3.7.0
Bump premailer from 3.6.1 to 3.7.0

Bumps [premailer](https://github.com/peterbe/premailer) from 3.6.1 to 3.7.0.
- [Release notes](https://github.com/peterbe/premailer/releases)
- [Changelog](https://github.com/peterbe/premailer/blob/master/CHANGES.rst)
- [Commits](https://github.com/peterbe/premailer/commits)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
annapowellsmith/openpresc,annapowellsmith/openpresc,annapowellsmith/openpresc,ebmdatalab/openprescribing,annapowellsmith/openpresc,ebmdatalab/openprescribing,ebmdatalab/openprescribing,ebmdatalab/openprescribing