shell.nix: use different cargoHash for Nixpkgs >= 25.05pre

It seems like something has changed in the way that Nix or Cargo
calculates the hash over the locked Cargo dependencies, which causes
builds to break on Nixpkgs >= 25.05.

For the time being, let's do a version check and support both Nixpkgs
>= 25.05pre and < 25.05pre with different `cargoHash`es.

Author: lschuermann

shell.nix

@@ -35,7 +35,11 @@ let
       sha256 = "sha256-+VeWLBI6md399Oaumt4pJrOkm0Nz7fmpXN2TjglUE34=";
     };
 
-    cargoHash = "sha256-UHAwk1fBcabRqy7VMhz4aoQuIur+MQshDOhC7KFyGm4=";
+    cargoHash =
+      if lib.versionAtLeast lib.version "25.05pre" then
+        "sha256-C1hg2/y557jRLkSBvFLxYKH+t8xEJudDvU72kO9sPug="
+      else
+        "sha256-UHAwk1fBcabRqy7VMhz4aoQuIur+MQshDOhC7KFyGm4=";
   };
 
   # The formatting scripts require a specific version of uncrustify: