dependency-track: pin nodejs_20 for frontend

Using node 22 results in this error when building:

> npm error node-pre-gyp http GET https://github.com/marudor/libxmljs2/releases/download/v0.33.0/node-v127-linux-x64-glibc.tar.gz
> npm error node-pre-gyp ERR! install request to https://github.com/marudor/libxmljs2/releases/download/v0.33.0/node-v127-linux-x64-glibc.tar.gz failed, reason: getaddrinfo EAI_AGAIN github.com

(cherry picked from commit 5967f89)

pkgs/by-name/de/dependency-track/package.nix

@@ -2,6 +2,7 @@
   lib,
   buildNpmPackage,
   fetchFromGitHub,
+  nodejs_20,
   jre_headless,
   protobuf,
   cyclonedx-cli,
@@ -17,6 +18,9 @@ let
     pname = "dependency-track-frontend";
     inherit version;
 
+    # TODO: pinned due to build error on node 22
+    nodejs = nodejs_20;
+
     src = fetchFromGitHub {
       owner = "DependencyTrack";
       repo = "frontend";