conditionally require cached-hafas-client 💚

https://github.com/derhuerst/vbb-rest/actions/runs/6233508017/job/16918905237

db-rest v5 equivalent: derhuerst/db-rest@72caa58

api.js

@@ -5,8 +5,6 @@ const parse = require('cli-native').to
 const createHafas = require('vbb-hafas')
 const createHealthCheck = require('hafas-client-health-check')
 const Redis = require('ioredis')
-const withCache = require('cached-hafas-client')
-const redisStore = require('cached-hafas-client/stores/redis')
 const createApi = require('hafas-rest-api')
 const serveStatic = require('serve-static')
 
@@ -32,6 +30,9 @@ let hafas = createHafas(
 let healthCheck = createHealthCheck(hafas, berlinFriedrichstr)
 
 if (process.env.REDIS_URL) {
+	const withCache = require('cached-hafas-client')
+	const redisStore = require('cached-hafas-client/stores/redis')
+
 	const redis = new Redis(process.env.REDIS_URL || null)
 	hafas = withCache(hafas, redisStore(redis))