release: Bump for 2.2 release cycle.

Author: davecgh

version.go

@@ -54,7 +54,7 @@ var (
 	// the app will panic at runtime.  Of particular note is the pre-release
 	// and build metadata portions MUST only contain characters from
 	// semanticAlphabet.
-	Version = "2.1.0-pre"
+	Version = "2.2.0-pre"
 
 	// NOTE: The following values are set via init by parsing the above Version
 	// string.