Fix a typo "uage" -> "usage" in `Feature Proposal - lean.md`

.gitlab/issue_templates/Feature Proposal - lean.md

@@ -40,7 +40,7 @@ Personas are described at https://about.gitlab.com/handbook/marketing/product-ma
 
 ### Metrics
 
-<!-- How are you going to track uage of this feature? Think about user behavior and their interaction with the product. What indicates someone is getting value from it?
+<!-- How are you going to track usage of this feature? Think about user behavior and their interaction with the product. What indicates someone is getting value from it?
 
 Create tracking issue using the Snowplow event tracking template. See https://gitlab.com/gitlab-org/gitlab/-/blob/master/.gitlab/issue_templates/Snowplow%20event%20tracking.md