Bump azure-mgmt-storage from 21.1.0 to 21.2.1

Bumps [azure-mgmt-storage](https://github.com/Azure/azure-sdk-for-python) from 21.1.0 to 21.2.1.
- [Release notes](https://github.com/Azure/azure-sdk-for-python/releases)
- [Changelog](https://github.com/Azure/azure-sdk-for-python/blob/main/doc/esrp_release.md)
- [Commits](Azure/azure-sdk-for-python@azure-mgmt-storage_21.1.0...azure-mgmt-storage_21.2.1)

---
updated-dependencies:
- dependency-name: azure-mgmt-storage
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

requirements.txt

@@ -2,7 +2,7 @@ boto3
 azure-identity==1.16.0
 azure-mgmt-compute==31.0.0
 azure-mgmt-resource==23.1.1
-azure-mgmt-storage==21.1.0
+azure-mgmt-storage==21.2.1
 azure-storage-blob==12.20.0
 cachetools
 msrestazure==0.6.4