Adds gl-button classes to fork suggestions

app/views/projects/_customize_workflow.html.haml

@@ -5,4 +5,4 @@
     %p
       Get started with GitLab by enabling features that work best for your project. From issues and wikis, to merge requests and pipelines, GitLab can help manage your workflow from idea to production!
     - if can?(current_user, :admin_project, @project)
-      = link_to "Get started", edit_project_path(@project), class: "btn btn-success"
+      = link_to "Get started", edit_project_path(@project), class: "gl-button btn btn-success"

app/views/projects/_fork_suggestion.html.haml

@@ -6,6 +6,6 @@
         edit
       files in this project directly. Please fork this project,
       make your changes there, and submit a merge request.
-    = link_to 'Fork', nil, method: :post, class: 'js-fork-suggestion-button btn btn-grouped btn-inverted btn-success'
-    %button.js-cancel-fork-suggestion-button.btn.btn-grouped{ type: 'button' }
+    = link_to 'Fork', nil, method: :post, class: 'js-fork-suggestion-button gl-button btn btn-grouped btn-inverted btn-success'
+    %button.js-cancel-fork-suggestion-button.gl-button.btn.btn-grouped{ type: 'button' }
       Cancel