Bump time-machine from 2.15.0 to 2.16.0 in /requirements

Bumps [time-machine](https://github.com/adamchainz/time-machine) from 2.15.0 to 2.16.0.
- [Changelog](https://github.com/adamchainz/time-machine/blob/main/CHANGELOG.rst)
- [Commits](adamchainz/time-machine@2.15.0...2.16.0)

---
updated-dependencies:
- dependency-name: time-machine
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements/common.txt

@@ -21,4 +21,4 @@ requests==2.32.3
 sorl-thumbnail==12.11.0
 Sphinx==8.1.3
 stripe==3.1.0
-time-machine==2.15.0
+time-machine==2.16.0