Public preview: Azure Spring Apps feature updates

The following updates are now available in both basic/standard and enterprise tiers: * **Custom Image Support as part of Spring Boot App:** You can now deploy Spring applications in Azure Spring Apps using a custom container image. [Learn more.](https://docs.microsoft.com/en-us/azure/spring-cloud/how-to-deploy-with-custom-container-image?tabs=azure-cli) * **Support user-assigned identity:** A common challenge for developers is the management of secrets, credentials, certificates, keys, etc. used to secure communication between services. You can now use managed identities to manage these credentials. User-assigned identity has an independent lifecycle and can be shares across multiple Azure resources. [Learn more.](https://docs.microsoft.com/en-us/azure/spring-cloud/how-to-manage-user-assigned-managed-identities) * **Application Change Analysis Integration:** Integrated with Change Analysis to provide insights into your Azure application changes, increases observability, and reduces mean time to repair (MTTR). [Learn more.](https://docs.microsoft.com/en-us/azure/azure-monitor/change/change-analysis) You can also learn more about the Azure Spring Apps Enterprise tier GA announcement by [Microsoft](https://techcommunity.microsoft.com/t5/apps-on-azure-blog/azure-spring-apps-enterprise-tier-is-now-generally-available/ba-p/3418245) and [VMWare](https://tanzu.vmware.com/content/blog/azure-spring-apps-enterprise). * Features