Update nlopt submodule

DanielBok · DanielBok · commit 808adb2b17ac · 2023-07-06T11:51:19.000+08:00
diff --git a/extern/nlopt b/extern/nlopt
@@ -1 +1 @@
-Subproject commit f8692f86b5269112b3760704093d0600adb033e7
+Subproject commit c40b5486c12da6eb994984021bfbfb2ef160cbf6
