avro

AVRO-4038: [C++] Add local-timestamp-nanos and timestamp-nanos (#3102)

* AVRO-4038: [C++] Add local-timestamp-nanos and timestamp-nanos

* Add "pull-requests: write" permission to the labeler

Copied from the example at https://github.com/actions/labeler?tab=readme-ov-file#outputs
Trying to fix https://github.com/apache/avro/actions/runs/10460767435/job/28981928566?pr=3102
```
Run actions/labeler@v5
  with:
    repo-token: ***
    sync-labels: true
    configuration-path: .github/labeler.yml
    dot: true
The configuration file (path: .github/labeler.yml) was not found locally, fetching via the api
Warning: The action requires write permission to add labels to pull requests. For more information please refer to the action documentation: https://github.com/actions/labeler#permissions
Error: Resource not accessible by integration
```

Signed-off-by: Martin Tzvetanov Grigorov <mgrigorov@apache.org>

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Signed-off-by: Martin Tzvetanov Grigorov <mgrigorov@apache.org>
Co-authored-by: Martin Tzvetanov Grigorov <mgrigorov@apache.org>