Update support version: 1.60.0 -> 1.61.0-beta01

Features

- googleapis#2429 Utilities for date/time parsing.
- googleapis#2394 Which improves impersonation support.
- googleapis#2349 and googleapis#2379 Which improve error reported when ADC is not configured.

Src/Support/CommonProjectProperties.xml

@@ -2,7 +2,7 @@
 
   <!-- common nupkg information -->
   <PropertyGroup>
-    <Version>1.60.0</Version>
+    <Version>1.61.0-beta01</Version>
     <Authors>Google LLC</Authors>
     <Copyright>Copyright 2021 Google LLC</Copyright>
     <PackageTags>Google</PackageTags>