bump versions to 2.8.4

apps/cli/executables/go/spelunker/main.go

@@ -46,7 +46,7 @@ func main() {
 
 	if *v {
 		//TODO: fix version system for containers
-		log.Println("2.8.3.dev1")
+		log.Println("2.8.4.dev1")
 		os.Exit(0)
 	}