Fix path to remove .md

Signed-off-by: Ronald Ngounou <[email protected]>

Author: ronaldngounou

content/en/docs/v3.5/upgrades/upgrade_3_1.md

@@ -5,7 +5,6 @@ description: Processes, checklists, and notes on upgrading etcd from 3.0 to 3.1
 ---
 
 In the general case, upgrading from etcd 3.0 to 3.1 can be a zero-downtime, rolling upgrade:
-
 - one by one, stop the etcd v3.0 processes and replace them with etcd v3.1 processes
 - after running all v3.1 processes, new features in v3.1 are available to the cluster
 
@@ -26,7 +25,7 @@ Following metrics from v3.0.x have been deprecated in favor of [go-grpc-promethe
 
 #### Upgrade requirements
 
-To upgrade an existing etcd deployment to 3.1, the running cluster must be 3.0 or greater. If it's before 3.0, please [upgrade to 3.0](../archives_upgrades/upgrade_3_0.md) before upgrading to 3.1.
+To upgrade an existing etcd deployment to 3.1, the running cluster must be 3.0 or greater. If it's before 3.0, please [upgrade to 3.0](../archives_upgrades/upgrade_3_0) before upgrading to 3.1.
 
 Also, to ensure a smooth rolling upgrade, the running cluster must be healthy. Check the health of the cluster by using the `etcdctl endpoint health` command before proceeding.