[Hub Generated] Review request for Microsoft.VirtualMachineImages to add version stable/2020-02-14 (#16725)

* update description for build vm size

* finalize str

Co-authored-by: rez1 <rez1@DESKTOP-2UNMLHO.redmond.corp.microsoft.com>

Author: rezmicrosoft

specification/imagebuilder/resource-manager/Microsoft.VirtualMachineImages/stable/2020-02-14/imagebuilder.json

@@ -946,7 +946,7 @@
         "vmSize": {
           "type": "string",
           "default": "",
-          "description": "Size of the virtual machine used to build, customize and capture images. Omit or specify empty string to use the default (Standard_D1_v2)."
+          "description": "Size of the virtual machine used to build, customize and capture images. Omit or specify empty string to use the default (Standard_D1_v2 for Gen1 images and Standard_D2ds_v4 for Gen2 images)."
         },
         "osDiskSizeGB": {
           "type": "integer",