cinny-unwrapped: pin Node 20 (#367182)

pkgs/by-name/ci/cinny-unwrapped/package.nix

···
   pango,
   stdenv,
   olm,
+  nodejs_20,
 }:
 
 buildNpmPackage rec {
···
     rev = "v${version}";
     hash = "sha256-BoUQURCfEu5kocMm8T25cVl8hgZGxcxrMzQZOl2fAbY=";
   };
+
+  # canvas, a transitive dependency of cinny, fails to build with Node 22
+  # https://github.com/Automattic/node-canvas/issues/2448
+  nodejs = nodejs_20;
 
   npmDepsHash = "sha256-fDoia6evCmXZgeIKL0coRo3yunX1dfud31ROgmop2Sc=";