Bump pygments from 2.11.2 to 2.15.0 in /examples/research_projects/decision_transformer (#24949)

Bump pygments in /examples/research_projects/decision_transformer

Bumps [pygments](https://github.com/pygments/pygments) from 2.11.2 to 2.15.0.
- [Release notes](https://github.com/pygments/pygments/releases)
- [Changelog](https://github.com/pygments/pygments/blob/master/CHANGES)
- [Commits](https://github.com/pygments/pygments/compare/2.11.2...2.15.0)

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

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examples/research_projects/decision_transformer/requirements.txt

@@ -157,7 +157,7 @@ pycodestyle==2.8.0
 pycparser==2.21
 pyctcdecode==0.3.0
 pyflakes==2.4.0
-Pygments==2.11.2
+Pygments==2.15.0
 pygtrie==2.4.2
 pynvml==11.4.1
 pyOpenSSL==22.0.0