Update release-notes.md

update release notes with hiding of DSVM 18 announcement

Author: jesscioffi

articles/machine-learning/data-science-virtual-machine/release-notes.md

@@ -21,6 +21,24 @@ Azure portal users will always find the latest image available for provisioning
 See the [list of known issues](reference-known-issues.md) to learn about known bugs and workarounds.
 
 
+## September 20, 2022
+**Announcement:**
+Ubuntu 18 DSVM will **not be** available on the marketplace starting Oct 1, 2022. We recommend users switch to Ubuntu 20 DSVM as we continue to ship updates/patches on our latest [Data Science VM – Ubuntu 20.04](https://azuremarketplace.microsoft.com/marketplace/apps/microsoft-dsvm.ubuntu-2004?tab=Overview)
+
+Users that are using Azure Resource Manager (ARM) template/virtual machine scale set to deploy the Ubuntu DSVM machines, should configure:
+
+| Offer | SKU |
+| --------- | ------------|
+| ubuntu-2004  | 2004 for Gen1 or 2004-gen2 for Gen2 VM sizes  |
+
+Instead of:
+
+| Offer | SKU |
+| --------- | ------------|
+| ubuntu-1804  | 1804 for Gen1 or 1804-gen2 for Gen2 VM sizes  |
+
+**Note**: There is no impact to existing customers who are still on Ubuntu-18 DSVM as of our October 2022 update. Howeverm the deprecation plan is scheduled for December 2022. We recommend that you switch to Ubuntu-20 DSVM at your earliest convenience.
+
 ## September 19, 2022
 [Data Science VM – Ubuntu 20.04](https://azuremarketplace.microsoft.com/marketplace/apps/microsoft-dsvm.ubuntu-2004?tab=Overview)