submodules: bump external/oasis-core from c4cdfca to ca29d1f

Bumps [external/oasis-core](https://github.com/oasisprotocol/oasis-core) from `c4cdfca` to `ca29d1f`.
- [Release notes](https://github.com/oasisprotocol/oasis-core/releases)
- [Commits](oasisprotocol/oasis-core@c4cdfca...ca29d1f)

---
updated-dependencies:
- dependency-name: external/oasis-core
  dependency-version: ca29d1f104bc4b0faec432f2bcd6d56c79df547a
  dependency-type: direct:production
...

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Author: dependabot[bot]