chore: Update lean4-nix (#27)

* chore: Update lean4-nix

* fix: Copy gitignored blake3 symlink

Author: samuelburnham

flake.lock

@@ -45,6 +45,9 @@
           // {
             name = "Blake3";
             buildLibrary = true;
+            postInstall = ''
+              cp -P ./blake3 $out
+            '';
           });
         blake3Test = lake2nix.mkPackage (commonArgs
           // {