Use a more lenient dependency version range specification for pygments

requirements/requirements-optionals.txt

@@ -6,5 +6,5 @@ django-guardian>=2.4.0,<2.5
 inflection==0.5.1
 markdown==3.3
 psycopg2-binary>=2.9.5,<2.10
-pygments==2.12
+pygments>=2.7.1,<3.0
 pyyaml>=5.3.1,<5.4

tests/test_renderers.py

@@ -1,6 +1,7 @@
 import re
 from collections import OrderedDict
 from collections.abc import MutableMapping
+from xml.etree import ElementTree
 
 import pytest
 from django.core.cache import cache
@@ -852,7 +853,8 @@ class TestDocumentationRenderer(TestCase):
             'link': coreapi.Link(url='/data/', action='get', fields=[]),
         }
         html = template.render(context)
-        assert 'testcases list' in html
+        text = "".join(ElementTree.fromstring(html).itertext())
+        assert 'testcases list' in text
 
 
 @pytest.mark.skipif(not coreapi, reason='coreapi is not installed')