Update README.zh-cn.md (#455)

Fix the link to pages of related lessons

Co-authored-by: Jim Bennett <jim.bennett@microsoft.com>

2-farm/translations/README.zh-cn.md

@@ -8,12 +8,12 @@
 
 ## 主题
 
-1. [应用物联网预测植物生长](lessons/1-predict-plant-growth/translations/README.zh-cn.md)
-1. [检测土壤湿度](lessons/2-detect-soil-moisture/README.md)
-1. [自动给植物浇水](lessons/3-automated-plant-watering/README.md)
-1. [将你的植物迁移到云端](lessons/4-migrate-your-plant-to-the-cloud/README.md)
-1. [将你的应用程序逻辑迁移到云端](lessons/5-migrate-application-to-the-cloud/README.md)
-1. [确保你的植物安全](lessons/6-keep-your-plant-secure/README.md)
+1. [应用物联网预测植物生长](../lessons/1-predict-plant-growth/translations/README.zh-cn.md)
+1. [检测土壤湿度](../lessons/2-detect-soil-moisture/README.md)
+1. [自动给植物浇水](../lessons/3-automated-plant-watering/README.md)
+1. [将你的植物迁移到云端](../lessons/4-migrate-your-plant-to-the-cloud/README.md)
+1. [将你的应用程序逻辑迁移到云端](../lessons/5-migrate-application-to-the-cloud/README.md)
+1. [确保你的植物安全](../lessons/6-keep-your-plant-secure/README.md)
 
 ## 作者