Pin perles package to specific commit for reproducibility

Replace rev = "main" with the specific commit hash 64eba96c0a9b663ef3a206c8f07b71ab34f46df4
to ensure reproducible builds. Using branch names as revisions can cause
unexpected changes when the upstream branch advances.

packages/perles/default.nix

@@ -7,7 +7,7 @@ buildGoModule rec {
   src = fetchFromGitHub {
     owner = "zjrosen";
     repo = "perles";
-    rev = "main";
+    rev = "64eba96c0a9b663ef3a206c8f07b71ab34f46df4";
     hash = "sha256-JgRayb4+mJ1r0AtdnQfqAw2+QRte+licsfZOaRgYqcs=";
   };