bump version

Author: kylebrandt

_version/version.go

@@ -11,7 +11,7 @@ import (
 // build.go will set date and sha, but `go get` will set none of these.
 var (
 	// Version number for official releases Updated manually before each release.
-	Version = "0.5.0-rc1"
+	Version = "0.5.0-rc2"
 
 	// Set to any non-empty value by official release script
 	OfficialBuild string