fix: remove extra substituters

Author: arntanguy

flake.nix

@@ -21,19 +21,6 @@
     with-python-trigger.url = "github:boolean-option/true";
   };
 
-  nixConfig = {
-    extra-substituters = [
-      "https://mc-rtc-nix.cachix.org"
-      "https://gepetto.cachix.org"
-      "https://attic.iid.ciirc.cvut.cz/ros"
-    ];
-    extra-trusted-public-keys = [
-      "mc-rtc-nix.cachix.org-1:5M3sLvHXJCep4wc1tQl7QuFWL2eH2I0jkuvWtqJDYQs="
-      "gepetto.cachix.org-1:toswMl31VewC0jGkN6+gOelO2Yom0SOHzPwJMY2XiDY="
-      "ros:JR95vUYsShSqfA1VTYoFt1Nz6uXasm5QrcOsGry9f6Q="
-    ];
-  };
-
   outputs =
     inputs:
     let