Configure upstream source for Universal Packages with Azure Artifacts

We are adding the ability to configure your upstream source for Universal Packages with this release. This feature will add the ability to configure your Azure Artifacts feeds to automatically download Universal Packages from upstream sources on demand. Other key features to enhance the overall user experience are now available: **Azure Boards** * [System work item types on backlogs and boards](https://docs.microsoft.com/en-us/azure/devops/release-notes/2020/sprint-174-update#system-work-item-types-on-backlogs-and-boards) * [Audit logging event](https://docs.microsoft.com/en-us/azure/devops/release-notes/2020/sprint-174-update#audit-logging-event) * [Azure Boards GitHub app repo limit raised (private preview)](https://docs.microsoft.com/en-us/azure/devops/release-notes/2020/sprint-174-update#azure-boards-github-app-repo-limit-raised-private-preview) * [Customise work item state when pull request is merged (private preview)](https://docs.microsoft.com/en-us/azure/devops/release-notes/2020/sprint-174-update#customize-work-item-state-when-pull-request-is-merged-private-preview) **Azure Pipelines** * [Pipelines images announcements](https://docs.microsoft.com/en-us/azure/devops/release-notes/2020/sprint-174-update#pipelines-images-announcements) * [Agent log uploads improved](https://docs.microsoft.com/en-us/azure/devops/release-notes/2020/sprint-174-update#agent-log-uploads-improved) * [Optionally mount container volumes read-only](https://docs.microsoft.com/en-us/azure/devops/release-notes/2020/sprint-174-update#optionally-mount-container-volumes-read-only) * [Fine-grained control over container start/stop](https://docs.microsoft.com/en-us/azure/devops/release-notes/2020/sprint-174-update#fine-grained-control-over-container-startstop) * [Unzip task bundles for each step](https://docs.microsoft.com/en-us/azure/devops/release-notes/2020/sprint-174-update#unzip-task-bundles-for-each-step) * [Improve release security by restricting scope of access tokens](https://docs.microsoft.com/en-us/azure/devops/release-notes/2020/sprint-174-update#improve-release-security-by-restricting-scope-of-access-tokens) * [YAML preview API enhancements](https://docs.microsoft.com/en-us/azure/devops/release-notes/2020/sprint-174-update#yaml-preview-api-enhancements) **Azure Artifacts** * [Configure upstream sources for Universal Packages](https://docs.microsoft.com/en-us/azure/devops/release-notes/2020/sprint-174-update#configure-upstream-sources-for-universal-packages) * [Update Package Version REST API now available for Maven packages](https://docs.microsoft.com/en-us/azure/devops/release-notes/2020/sprint-174-update#update-package-version-rest-api-now-available-for-maven-packages) * Azure DevOps Projects * Features * [ Azure DevOps Projects](https://azure.microsoft.com/en-gb/features/devops-projects/)