Fix float-right mixin build warning

Bootstrap Sass mixin float-right is deprecated, swapped to use
utitlity class instead.
This will fix warning:
WARNING: The `float-right` mixin has been deprecated as of v4.3.0.
It will be removed entirely in v5.

Signed-off-by: Yoshie Muranaka <yoshiemuranaka@gmail.com>
Change-Id: Ib94fff09c9c218143335f9021e0dfe213294b426
diff --git a/src/views/Overview/OverviewEvents.vue b/src/views/Overview/OverviewEvents.vue
index af86e79..9d02d1c 100644
--- a/src/views/Overview/OverviewEvents.vue
+++ b/src/views/Overview/OverviewEvents.vue
@@ -5,7 +5,7 @@
     </div>
     <div v-else>
       <!-- TODO: link to event log -->
-      <b-button variant="link" href="#">
+      <b-button variant="link" href="#" class="float-right">
         {{ $t('pageOverview.events.viewAllButton') }}
       </b-button>
       <b-table
@@ -70,10 +70,6 @@
 </script>
 
 <style lang="scss" scoped>
-.btn {
-  @include float-right;
-}
-
 .date-column {
   min-width: 200px;
 }