Fix the groupLabelsPath in app/assets/javascripts/api.js

Signed-off-by: Rémy Coutable <remy@rymai.me>

app/assets/javascripts/api.js

@@ -9,7 +9,7 @@ const Api = {
   projectsPath: '/api/:version/projects.json',
   projectPath: '/api/:version/projects/:id',
   projectLabelsPath: '/:namespace_path/:project_path/labels',
-  groupLabelsPath: '/groups/:namespace_path/labels',
+  groupLabelsPath: '/groups/:namespace_path/-/labels',
   licensePath: '/api/:version/templates/licenses/:key',
   gitignorePath: '/api/:version/templates/gitignores/:key',
   gitlabCiYmlPath: '/api/:version/templates/gitlab_ci_ymls/:key',