Bump pygments from 2.10.0 to 2.15.0 in /ICLR2023

Bumps [pygments](https://github.com/pygments/pygments) from 2.10.0 to 2.15.0.
- [Release notes](https://github.com/pygments/pygments/releases)
- [Changelog](https://github.com/pygments/pygments/blob/master/CHANGES)
- [Commits](pygments/pygments@2.10.0...2.15.0)

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

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

Author: dependabot[bot]

ICLR2023/requirements.txt

@@ -174,7 +174,7 @@ pyasn1-modules==0.2.1
 pycparser==2.20
 pycrypto==2.6.1
 pydantic==1.8.2
-Pygments==2.10.0
+Pygments==2.15.0
 PyGObject==3.26.1
 PyJWT==2.4.0
 pyOpenSSL==17.5.0