Bump debugpy from 1.8.20 to 1.8.21

Bumps [debugpy](https://github.com/microsoft/debugpy) from 1.8.20 to 1.8.21.
- [Release notes](https://github.com/microsoft/debugpy/releases)
- [Commits](microsoft/debugpy@v1.8.20...v1.8.21)

---
updated-dependencies:
- dependency-name: debugpy
  dependency-version: 1.8.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

requirements.txt

@@ -66,7 +66,7 @@ dask==2026.3.0
     # via
     #   qcodes (pyproject.toml)
     #   qcodes
-debugpy==1.8.20
+debugpy==1.8.21
     # via ipykernel
 decorator==5.3.1
     # via ipython