Bump riscv-opcodes from `902fa8a` to `ed68c21`

Bumps [riscv-opcodes](https://github.com/riscv/riscv-opcodes) from `902fa8a` to `ed68c21`.
- [Release notes](https://github.com/riscv/riscv-opcodes/releases)
- [Commits](https://github.com/riscv/riscv-opcodes/compare/902fa8a1b66e9cb661f9772c2a833d7e16e5670d...ed68c21b025ced3e09bc6ad753947ec8248f89ec

)

---
updated-dependencies:
- dependency-name: riscv-opcodes
  dependency-type: direct:production
...

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