Nix expr: Remove unused pinned Nixpkgs from nixpkgs.nix

fixes 1e51cfa

Author: YoshiRulz

Dist/nixpkgs.nix

@@ -3,10 +3,6 @@
 		url = "https://github.com/YoshiRulz/nixpkgs/archive/a9302067440792f6137e4e96f3bfcbb1ed086eb2.tar.gz"; # .NET 10 backported to 24.05, since that was the last release before ebd3b37e6, see https://github.com/NixOS/nixpkgs/pull/327651#issuecomment-3499977198
 		sha256 = "1app1qh40blfr2r1dkkpp7r22kmbq50x4zicrak8rrcgamxd0lxb";
 	}) { inherit system; };
-	nixpkgs-23_05 = system: fetchzip: import (fetchzip {
-		url = "https://github.com/NixOS/nixpkgs/archive/23.05.tar.gz";
-		hash = "sha512-REPJ9fRKxTefvh1d25MloT4bXJIfxI+1EvfVWq644Tzv+nuq2BmiGMiBNmBkyN9UT5fl2tdjqGliye3gZGaIGg==";
-	}) { inherit system; };
 	nixpkgs-22_11-with-dotnet-5 = system: fetchzip: import (fetchzip {
 		url = "https://github.com/NixOS/nixpkgs/archive/a8f575995434695a10b574d35ca51b0f26ae9049.tar.gz"; # commit immediately before .NET 5 was removed
 		hash = "sha512-3ysJjKK1lYV1r/zLohyuD1fiK+8TD3MMA3TrX9fb42nKqzfGGW62Aom7ltiyyxbVbBYOCXUy41Z5Y0j2VOxRKw==";