Fix borders in the commit sha group

Fixes the incorrect borders in the copy commit sha group

app/assets/stylesheets/pages/commits.scss

@@ -208,9 +208,9 @@
   display: inline-flex;
 
   .label,
-  .btn {
+  .btn:not(.gl-button) {
     padding: $gl-vert-padding $gl-btn-padding;
-    border: 1px $border-color solid;
+    border: 1px $gray-200 solid;
     font-size: $gl-font-size;
     line-height: $line-height-base;
     border-radius: 0;

app/views/projects/commits/_commit.html.haml

@@ -57,7 +57,7 @@
 
       .js-commit-pipeline-status{ data: { endpoint: pipelines_project_commit_path(project, commit.id, ref: ref) } }
 
-      .commit-sha-group.d-none.d-sm-flex
+      .commit-sha-group.btn-group.d-none.d-sm-flex
         .label.label-monospace.monospace
           = commit.short_id
         = clipboard_button(text: commit.id, title: _("Copy commit SHA"), class: "gl-button btn btn-default", container: "body")