build(deps): bump pygments from 2.11.2 to 2.15.0 in /requirements/tox (#4010)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements/tox/doc8_requirements.txt

@@ -1,2 +1,2 @@
 doc8==0.10.1
-Pygments==2.11.2
+Pygments==2.15.0