Add more spacing between related changes sections

Change-Id: Ifaf8c36bc333856f212f2e1e1c7f7df88ac78bd0
diff --git a/polygerrit-ui/app/elements/change/gr-related-changes-list-experimental/gr-related-changes-list-experimental.ts b/polygerrit-ui/app/elements/change/gr-related-changes-list-experimental/gr-related-changes-list-experimental.ts
index abac54c..659ef4f 100644
--- a/polygerrit-ui/app/elements/change/gr-related-changes-list-experimental/gr-related-changes-list-experimental.ts
+++ b/polygerrit-ui/app/elements/change/gr-related-changes-list-experimental/gr-related-changes-list-experimental.ts
@@ -105,7 +105,7 @@
           margin-left: 1.2em;
         }
         section {
-          margin-bottom: var(--spacing-m);
+          margin-bottom: var(--spacing-l);
         }
         gr-related-change {
           display: flex;