Update azure-keyvault-secrets requirement from ==4.4.* to ==4.8.*

Updates the requirements on [azure-keyvault-secrets](https://github.com/Azure/azure-sdk-for-python) to permit the latest version.
- [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-keyvault-secrets_4.4.0b1...azure-keyvault-secrets_4.8.0)

---
updated-dependencies:
- dependency-name: azure-keyvault-secrets
  dependency-type: direct:production
...

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

requirements.txt

@@ -31,4 +31,4 @@ evaluate==0.4.1
 azure-ai-textanalytics==5.3.0
 azure.ai.documentintelligence==1.0.0b1
 levenshtein==0.25.0
-azure-keyvault-secrets==4.4.*
+azure-keyvault-secrets==4.8.*