Increment Build Versions (#2188)

Author: brianrob

src/Directory.Build.props

@@ -19,7 +19,7 @@
 
   <PropertyGroup>
     <!-- These are the versions of the things we are CREATING in this repository -->
-    <ReleaseVersion>3.1.20</ReleaseVersion>
+    <ReleaseVersion>3.1.21</ReleaseVersion>
     <FastSerializationVersion>$(ReleaseVersion)</FastSerializationVersion>
     <HeapDumpDllVersion>$(ReleaseVersion)</HeapDumpDllVersion>
     <MemoryGraphVersion>$(ReleaseVersion)</MemoryGraphVersion>