devel/py-azure-mgmt-postgresqlflexibleservers: Update to 3.0.0b1
Changes: https://github.com/Azure/azure-sdk-for-python/releases
https://github.com/Azure/azure-sdk-for-python/blob/main/sdk/postgresqlflexibleservers/azure-mgmt-postgresqlflexibleservers/CHANGELOG.md