Update ordered-set requirement from ==3.* to ==4.*

Updates the requirements on [ordered-set](https://github.com/LuminosoInsight/ordered-set) to permit the latest version.
- [Release notes](https://github.com/LuminosoInsight/ordered-set/releases)
- [Commits](https://github.com/LuminosoInsight/ordered-set/commits)

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

requirements.txt

@@ -2,4 +2,4 @@ python-dateutil>=2.7.*
 inflection>=0.3.*
 unidecode>=1.0.*
 Jinja2>=2.10.*
-ordered-set==3.*
+ordered-set==4.*