build(deps): bump ostree-ext from 0.13.3 to 0.13.4

Bumps [ostree-ext](https://github.com/ostreedev/ostree-rs-ext) from 0.13.3 to 0.13.4.
- [Release notes](https://github.com/ostreedev/ostree-rs-ext/releases)
- [Commits](ostreedev/ostree-rs-ext@ostree-ext-v0.13.3...ostree-ext-v0.13.4)

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

Signed-off-by: dependabot[bot] <[email protected]>