nginxMainline: 1.31.2 -> 1.31.3

https://github.com/nginx/nginx/releases/tag/release-1.31.3

fixes:
- CVE-2026-42533
- CVE-2026-60005
- CVE-2026-56434

pkgs/servers/http/nginx/mainline.nix

@@ -1,6 +1,6 @@
 { callPackage, ... }@args:
 
 callPackage ./generic.nix args {
-  version = "1.31.2";
-  hash = "sha256-ryqVfEHaY23cT4g+RSPG0UC0eE285CAAw2SuUJKqRzw=";
+  version = "1.31.3";
+  hash = "sha256-p2V8UIEcLZLZiVOV6Lhz72A5gULE2yHrZHgRw49t1SU=";
 }