Bump node from 20-slim to 23-slim

Bumps node from 20-slim to 23-slim.

---
updated-dependencies:
- dependency-name: node
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Dockerfile

@@ -1,7 +1,7 @@
 ###### FRONTEND ######
 
 # Build frontend resources in node container
-FROM node:20-slim AS frontend-build
+FROM node:23-slim AS frontend-build
 
 # Build with npm
 COPY frontend /build/flugbuech/