Bump apache-airflow from 2.6.3 to 2.7.3

Bumps [apache-airflow](https://github.com/apache/airflow) from 2.6.3 to 2.7.3.
- [Release notes](https://github.com/apache/airflow/releases)
- [Changelog](https://github.com/apache/airflow/blob/main/RELEASE_NOTES.rst)
- [Commits](apache/airflow@2.6.3...2.7.3)

---
updated-dependencies:
- dependency-name: apache-airflow
  dependency-type: direct:production
...

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Author: dependabot[bot]