update version in constants

Author: jarlah

lib/constants.ex

@@ -1,6 +1,6 @@
 defmodule Testcontainers.Constants do
   def library_name, do: :testcontainers
-  def library_version, do: "1.2.3"
+  def library_version, do: "1.2.4"
   def container_label, do: "org.testcontainers"
   def container_lang_label, do: "org.testcontainers.lang"
   def container_lang_value, do: Elixir |> Atom.to_string() |> String.downcase()