Update _index.md

Author: lizwar

content/learning-paths/servers-and-cloud-computing/envoy/_index.md

@@ -13,7 +13,7 @@ learning_objectives:
     - Verify Envoy is working correctly
 
 prerequisites:
-    - To run envoy as a web server, you will need at least one [Arm based instance](/learning-paths/servers-and-cloud-computing/csp/) from a cloud service provider or an on-premises Arm server.
+    - To run Envoy as a web server, you will need at least one [Arm based instance](/learning-paths/servers-and-cloud-computing/csp/) from a cloud service provider or an on-premises Arm server.
     - Network settings (firewalls and security groups) which allow communication on port 22 (SSH) and port 80 (HTTP).
 
 author_primary: Zhengjun Xing