Bump pygments from 2.9.0 to 2.15.0

Bumps [pygments](https://github.com/pygments/pygments) from 2.9.0 to 2.15.0.
- [Release notes](https://github.com/pygments/pygments/releases)
- [Changelog](https://github.com/pygments/pygments/blob/master/CHANGES)
- [Commits](pygments/pygments@2.9.0...2.15.0)

---
updated-dependencies:
- dependency-name: pygments
  dependency-type: direct:production
...

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

requirements.txt

@@ -69,7 +69,7 @@ pycodestyle==2.7.0
 pycparser==2.20
 pycryptodome==3.10.1
 pyflakes==2.3.1
-Pygments==2.9.0
+Pygments==2.15.0
 pylint==2.8.2
 pyparsing==2.4.7
 pyrsistent==0.17.3