Fixed the upgrade indicator

src/pug/index.pug

@@ -76,8 +76,7 @@ html(lang="en")
               | v{{config.full_version}}
               a.upgrade-link(v-if="show_upgrade()", href="#admin-general")
                 | Upgrade to v{{latestVersion}}
-              .upgrade-attention(v-if="show_upgrade()")
-                | !
+              .fa.fa-exclamation-circle.upgrade-attention(v-if="show_upgrade()")
 
           .pi-temp-warning
             .fa.fa-thermometer-full(class="error",

src/stylus/style.styl

@@ -60,16 +60,10 @@ tt
         color blue
 
       .upgrade-attention
-        background-color red
-        width 20px
-        height 20px
-        display inline-block
-        border-radius 50%
-        color white
-        font-size 13pt
-        font-weight 1000
-        margin-left 5px
+        color red
+        font-size 18pt
         align-self center
+        margin-left 5px
 
   .pi-temp-warning
     align-self center