Bump extern/openPMD-api from ec449af to 6e2ace5

Bumps [extern/openPMD-api](https://github.com/openPMD/openPMD-api) from `ec449af` to `6e2ace5`.
- [Release notes](https://github.com/openPMD/openPMD-api/releases)
- [Commits](openPMD/openPMD-api@ec449af...6e2ace5)

---
updated-dependencies:
- dependency-name: extern/openPMD-api
  dependency-version: 6e2ace56c8f35666b2151f58180618224afde1a8
  dependency-type: direct:production
...

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Author: dependabot[bot]