Bump mistune in /ai/gen-ai-agents/custom-rag-agent/files

Bumps [mistune](https://github.com/lepture/mistune) from 3.1.2 to 3.2.1.
- [Release notes](https://github.com/lepture/mistune/releases)
- [Changelog](https://github.com/lepture/mistune/blob/main/docs/changes.rst)
- [Commits](lepture/mistune@v3.1.2...v3.2.1)

---
updated-dependencies:
- dependency-name: mistune
  dependency-version: 3.2.1
  dependency-type: direct:production
...

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

Author: dependabot[bot]

ai/gen-ai-agents/custom-rag-agent/files/requirements.txt

@@ -107,7 +107,7 @@ matplotlib-inline==0.1.7
 mccabe==0.7.0
 mcp==1.23.0
 mdurl==0.1.2
-mistune==3.1.2
+mistune==3.2.1
 mpmath==1.3.0
 msgpack==1.1.0
 multidict==6.1.0