cmd/geth: bump version number

cmd/geth/main.go

@@ -47,7 +47,7 @@ import _ "net/http/pprof"
 
 const (
 	ClientIdentifier = "Geth"
-	Version          = "0.9.12"
+	Version          = "0.9.13"
 )
 
 var app = utils.NewApp(Version, "the go-ethereum command line interface")