Fix front-end tests

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

js/src/components/Post/PostElementItem.vue

@@ -47,6 +47,7 @@
             <small class="has-text-grey-dark">{{
               $options.filters.formatDateTimeString(
                 new Date(post.insertedAt),
+                undefined,
                 false
               )
             }}</small>

js/src/views/Posts/Post.vue

@@ -29,6 +29,7 @@
                 :title="
                   $options.filters.formatDateTimeString(
                     post.updatedAt,
+                    undefined,
                     true,
                     'short'
                   )