Convert glDeprecatedButton to glButton in empty_rule.vue

ee/app/assets/javascripts/approvals/components/empty_rule.vue

 <script>
 import { mapActions } from 'vuex';
-import { GlDeprecatedButton } from '@gitlab/ui';
+import { GlButton } from '@gitlab/ui';
 import RuleInput from './mr_edit/rule_input.vue';
 import EmptyRuleName from './empty_rule_name.vue';
 import RuleBranches from './rule_branches.vue';
@@ -10,7 +10,7 @@ export default {
     RuleInput,
     EmptyRuleName,
     RuleBranches,
-    GlDeprecatedButton,
+    GlButton,
   },
   props: {
     rule: {
@@ -59,14 +59,14 @@ export default {
       <rule-input :rule="rule" :is-mr-edit="isMrEdit" />
     </td>
     <td>
-      <gl-deprecated-button
+      <gl-button
         v-if="!allowMultiRule && canEdit"
         class="ml-auto btn-info btn-inverted"
         data-qa-selector="add_approvers_button"
         @click="openCreateModal(null)"
       >
         {{ __('Add approval rule') }}
-      </gl-deprecated-button>
+      </gl-button>
     </td>
   </tr>
 </template>

ee/spec/frontend/approvals/components/mr_edit/empty_rule_spec.js

 import { shallowMount } from '@vue/test-utils';
 import EmptyRule from 'ee/approvals/components/empty_rule.vue';
-import { GlDeprecatedButton } from '@gitlab/ui';
+import { GlButton } from '@gitlab/ui';
 
 describe('Empty Rule', () => {
   let wrapper;
@@ -25,7 +25,7 @@ describe('Empty Rule', () => {
         allowMultiRule: true,
         canEdit: true,
       });
-      expect(wrapper.find(GlDeprecatedButton).exists()).toBe(false);
+      expect(wrapper.find(GlButton).exists()).toBe(false);
     });
   });
 
@@ -36,7 +36,7 @@ describe('Empty Rule', () => {
         canEdit: true,
       });
 
-      expect(wrapper.find(GlDeprecatedButton).exists()).toBe(true);
+      expect(wrapper.find(GlButton).exists()).toBe(true);
     });
 
     it('does not display "Add approval rule" button if not allowed to edit', () => {
@@ -44,7 +44,7 @@ describe('Empty Rule', () => {
         allowMultiRule: true,
         canEdit: false,
       });
-      expect(wrapper.find(GlDeprecatedButton).exists()).toBe(false);
+      expect(wrapper.find(GlButton).exists()).toBe(false);
     });
   });
 });