GitLab Free is the latest tier name

Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

.gitlab/issue_templates/Feature proposal.md

@@ -111,7 +111,7 @@ Use the following resources to find the appropriate labels:
 - https://about.gitlab.com/handbook/product/categories/features/
 -->
 /label ~devops:: ~group: ~Category:
-/label  ~"GitLab Core"/~"GitLab Premium"/~"GitLab Ultimate"
+/label  ~"GitLab Free"/~"GitLab Premium"/~"GitLab Ultimate"
 /label ~feature
 /label ~documentation
 /label ~direction