build(deps): bump opentelemetry-proto in /src/rust/sumologic-mock

Bumps [opentelemetry-proto](https://github.com/open-telemetry/opentelemetry-rust) from 0.6.0 to 0.26.0.
- [Release notes](https://github.com/open-telemetry/opentelemetry-rust/releases)
- [Commits](open-telemetry/opentelemetry-rust@opentelemetry-proto-0.6.0...opentelemetry-proto-0.26.0)

---
updated-dependencies:
- dependency-name: opentelemetry-proto
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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