build(deps): bump ujson from 5.5.0 to 5.6.0

Bumps [ujson](https://github.com/ultrajson/ultrajson) from 5.5.0 to 5.6.0.
- [Release notes](https://github.com/ultrajson/ultrajson/releases)
- [Commits](https://github.com/ultrajson/ultrajson/compare/5.5.0...5.6.0)

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

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

requirements.txt

@@ -71,7 +71,7 @@ soupsieve==2.3.2.post1
 testtools==2.5.0
 tlslite-ng==0.7.6
 tweepy==4.12.1
-ujson==5.5.0
+ujson==5.6.0
 update-checker==0.18.0
 urllib3==1.26.13
 webapp2==3.0.0b1