Add API v4.90.3 Changelog

Author: bbiggerr

src/content/changelog/4-90-3-2021-04-28.md

@@ -0,0 +1,11 @@
+---
+title: '4.90.3: 2021-04-28'
+date: 2021-04-28T04:00:00.000Z
+version: 4.90.3
+changelog:
+  - API
+---
+
+### Added
+
+- The Machine Image Upload ([POST /images/upload](https://www.linode.com/docs/api/images/#machine-image-upload)) beta endpoint has been added. This endpoint can be used to initiate a Machine Image upload by creating a new private Image object and returning it, along with the URL the image data can be uploaded to.