Bump pygments from 2.12.0 to 2.18.0

Bumps [pygments](https://github.com/pygments/pygments) from 2.12.0 to 2.18.0.
- [Release notes](https://github.com/pygments/pygments/releases)
- [Changelog](https://github.com/pygments/pygments/blob/master/CHANGES)
- [Commits](pygments/pygments@2.12.0...2.18.0)

---
updated-dependencies:
- dependency-name: pygments
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

requirements/base.txt

@@ -11,7 +11,7 @@ django-taggit==3.0.0
 ipython==7.33.0
 Markdown==3.4.4
 Pillow==9.1.0
-Pygments==2.12.0
+Pygments==2.18.0
 python-akismet==0.4.2
 requests==2.26.0
 six==1.15.0