Use anchor instead of form for reset caches button

app/assets/javascripts/pipelines/components/nav_controls.vue

@@ -50,9 +50,13 @@ export default {
       Get started with Pipelines
     </a>
 
-    <form :action="resetCachePath" method="post">
-      <input type="submit" class="btn btn-default" value="Clear runner caches" />
-    </form>
+    <a
+      data-method="post"
+      rel="nofollow"
+      :href="resetCachePath"
+      class="btn btn-default">
+      Clear runner caches
+    </a>
 
     <a
       :href="ciLintPath"

spec/javascripts/pipelines/nav_controls_spec.js

@@ -58,7 +58,7 @@ describe('Pipelines Nav Controls', () => {
     }).$mount();
 
     expect(component.$el.querySelectorAll('.btn-default')[0].textContent).toContain('Clear runner caches');
-    expect(component.$el.querySelector('form').getAttribute('action')).toEqual(mockData.resetCachePath);
+    expect(component.$el.querySelectorAll('.btn-default')[0].getAttribute('href')).toEqual(mockData.resetCachePath);
   });
 
   it('should render link for CI lint', () => {