Update drf-spectacular to 0.26.4 (#4481)

{{cookiecutter.project_slug}}/requirements/base.txt

@@ -43,7 +43,7 @@ django-redis==5.3.0  # https://github.com/jazzband/django-redis
 djangorestframework==3.14.0  # https://github.com/encode/django-rest-framework
 django-cors-headers==4.2.0  # https://github.com/adamchainz/django-cors-headers
 # DRF-spectacular for api documentation
-drf-spectacular==0.26.3  # https://github.com/tfranzel/drf-spectacular
+drf-spectacular==0.26.4  # https://github.com/tfranzel/drf-spectacular
 {%- endif %}
 {%- if cookiecutter.frontend_pipeline == 'Webpack' %}
 django-webpack-loader==2.0.1  # https://github.com/django-webpack/django-webpack-loader