factorio: bump to 0.18.40

Change-Id: I065a5e8a8c6608a137c0ae4f1cb04f8254ef6ddd
diff --git a/third_party/factorio/factorio.bzl b/third_party/factorio/factorio.bzl
index b0d661e..1ec71d2 100644
--- a/third_party/factorio/factorio.bzl
+++ b/third_party/factorio/factorio.bzl
@@ -23,6 +23,7 @@
     "0.18.12": "e0c6a46d66cfc02cba294a5fd34265e7e7a5168b8c8a7b16ad8dbac31470ed33",
     "0.18.17": "42adce9fddde393023afb0aae19dd030a32ca0810191c0e7b9b7c55556e9bbce",
     "0.18.22": "d90e349b61182c1e48bd34797faedc2f9b5b4e349d218ef3d987ae9d90762f7f",
+    "0.18.40": "696fe660fea945f38d12d49cf0b4737522d061fab5b3afd59467c4b2e375711a",
 }
 
 def factorio_repository(version, sha256):