chore: bump go to 1.26 and nix flake update

Signed-off-by: Alexander Trost <galexrt@googlemail.com>

Author: galexrt

flake.lock

@@ -9,7 +9,7 @@
   outputs = { self, nixpkgs }:
     let
       goMajorVersion = 1;
-      goMinorVersion = 25; # Change this to update the whole stack
+      goMinorVersion = 26; # Change this to update the whole stack
 
       lib = nixpkgs.lib;