fix: use PORT rather than hardcoding 3000

Author: tefkah

Dockerfile

@@ -132,6 +132,6 @@ COPY --from=withpackage --chown=node:node /usr/src/app/core/public ./core/public
 # needed to set the database url correctly based on PGHOST variables
 COPY --from=withpackage --chown=node:node /usr/src/app/core/.env.docker ./core/.env
 
-HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 CMD curl -f http://localhost:3000/api/health || exit 1
+HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 CMD ["curl", "-f", "http://localhost:${PORT}/api/health"]
 
 CMD ["node", "core/server.js"]