zh-trans: add case-studies/_index.html (#11245)

* zh-trans: add case-studies/_index.html

* Update _index.html

content/zh/case-studies/_index.html

@@ -0,0 +1,23 @@
+---
+title: 案例研究
+linkTitle: 案例研究
+bigheader: Kubernetes 用户案例研究
+abstract: 在生产环境中运行 Kubernetes 的用户集合。
+layout: basic
+class: gridPage
+cid: caseStudies
+---
+
+<!--
+
+---
+title: Case Studies
+linkTitle: Case Studies
+bigheader: Kubernetes User Case Studies
+abstract: A collection of users running Kubernetes in production.
+layout: basic
+class: gridPage
+cid: caseStudies
+---
+
+-->