Bump apache-airflow from 1.10.15 to 2.9.0

Bumps [apache-airflow](https://github.com/apache/airflow) from 1.10.15 to 2.9.0.
- [Release notes](https://github.com/apache/airflow/releases)
- [Changelog](https://github.com/apache/airflow/blob/main/RELEASE_NOTES.rst)
- [Commits](apache/airflow@1.10.15...2.9.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

requirements.txt

@@ -1,4 +1,4 @@
-apache-airflow==1.10.15
+apache-airflow==2.9.0
 azure-mgmt-hdinsight~=1.5.1
 msrestazure~=0.6.4
 mock~=4.0.2