Bump feynml from 0.2.1 to 0.2.4

Bumps [feynml](https://github.com/APN-Pucky/feynml) from 0.2.1 to 0.2.4.
- [Commits](APN-Pucky/feynml@0.2.1...0.2.4)

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

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