Change Icon component in HTML to kebab-case

app/assets/javascripts/diffs/components/compare_versions_dropdown.vue

@@ -115,7 +115,7 @@ export default {
       <span>
         {{ selectedVersionName }}
       </span>
-      <Icon
+      <icon
         :size="12"
         name="angle-down"
         class="position-absolute"

app/assets/javascripts/vue_shared/components/notes/system_note.vue

@@ -109,7 +109,7 @@ export default {
               class="system-note-commit-list-toggler flex-row"
               @click="expanded = !expanded"
             >
-              <Icon
+              <icon
                 :name="toggleIcon"
                 :size="8"
                 class="append-right-5"