Update drf-spectacular requirement in /requirements (#119)

Updates the requirements on [drf-spectacular](https://github.com/tfranzel/drf-spectacular) to permit the latest version.
- [Release notes](https://github.com/tfranzel/drf-spectacular/releases)
- [Changelog](https://github.com/tfranzel/drf-spectacular/blob/master/CHANGELOG.rst)
- [Commits](tfranzel/drf-spectacular@0.22.0...0.26.1)

---
updated-dependencies:
- dependency-name: drf-spectacular
  dependency-type: direct:production
...

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requirements/project-requirements.txt

@@ -4,5 +4,5 @@ Django~=3.2.18
 psycopg2-binary~=2.9.2
 slack-sdk~=3.12.0
 djangorestframework~=3.13.1
-drf-spectacular~=0.22.0
+drf-spectacular~=0.26.1
 certego-saas~=0.2.0