Bump webob from 1.8.7 to 1.8.8 in /requirements

Bumps [webob](https://github.com/Pylons/webob) from 1.8.7 to 1.8.8.
- [Changelog](https://github.com/Pylons/webob/blob/main/CHANGES.txt)
- [Commits](Pylons/webob@1.8.7...1.8.8)

---
updated-dependencies:
- dependency-name: webob
  dependency-type: indirect
...

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