Update custom.props for UWP object model release (#8393)

Author: anna-dingler

custom.props

@@ -1,10 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup Label="Version">
-    <VersionMajor>3</VersionMajor>
-    <VersionMinor>1</VersionMinor>
+    <VersionMajor>1</VersionMajor>
+    <VersionMinor>2</VersionMinor>
     <!-- The nuget package version should be incremented when we produce QFEs -->
-    <NuGetPackVersion>3.1.1</NuGetPackVersion>
+    <NuGetPackVersion>1.2.0</NuGetPackVersion>
     <VersionInfoProductName>AdaptiveCards</VersionInfoProductName>
   </PropertyGroup>
 </Project>