Add min attribute to project_limit field on user's form

CHANGELOG

@@ -57,6 +57,7 @@ v 8.10.0 (unreleased)
   - Add date when user joined the team on the member page
   - Fix 404 redirect after validation fails importing a GitLab project
   - Added setting to set new users by default as external !4545 (Dravere)
+  - Add min value for project limit field on user's form !3622 (jastkand)
 
 v 8.9.5
   - Add more debug info to import/export and memory killer. !5108

app/views/admin/users/_form.html.haml

@@ -44,7 +44,7 @@
       %legend Access
       .form-group
         = f.label :projects_limit, class: 'control-label'
-        .col-sm-10= f.number_field :projects_limit, class: 'form-control'
+        .col-sm-10= f.number_field :projects_limit, min: 0, class: 'form-control'
 
       .form-group
         = f.label :can_create_group, class: 'control-label'