Update Yaru to new Dash-to-Dock code

Some changes were required in the scss to make Dash to Dock
compatible with Gnome Shell 46, while also keeping compatibility
with Gnome Shell 45. These are those changes.

gnome-shell/src/gnome-shell-sass/_dock.scss

@@ -15,6 +15,8 @@ $dock_edge_items_padding: $dash_padding - $dock_spacing;
 $dock_fixed_inner_margin: $dock_side_margin;
 $dock_icons_distance: 4px;
 
+$remark_color: rgba(238, 238, 236, 0.2);
+
 @function shrink($val) {
     @return round($val / 4);
 }
@@ -186,7 +188,8 @@ $dock_style_modes: [null, shrink, extended, extended-shrink];
                     0, $dock_icons_distance / 2);
 
                 .app-well-app,
-                .show-apps {
+                .show-apps,
+                .overview-tile {
                     @include set-internal-children-property($side, padding, $spacing);
                     padding-#{$side}: $padding + $side_margin;
                     padding-#{opposite($side)}: $padding;
@@ -197,7 +200,7 @@ $dock_style_modes: [null, shrink, extended, extended-shrink];
                         background-image: none;
                     }
                     &.focused .overview-icon {
-                        background-color: rgba(238, 238, 236, 0.2);
+                        background-color: $remark_color;
                     }
 
                     .app-well-app-running-dot {
@@ -230,6 +233,20 @@ $dock_style_modes: [null, shrink, extended, extended-shrink];
     }
 }
 
+.overview-tile {
+    margin: 0px;
+    padding: 0px;
+    border: 0px;
+}
+
+.overview-tile .overview-icon, .show-apps .overview-icon {
+    background-color: rgba(255,255,255,0);
+}
+
+.overview-tile:hover .overview-icon, .overview-tile.focused .overview-icon, .show-apps:hover .overview-icon {
+    background-color: $remark_color;
+}
+
 @each $side in $dock_sides {
     @each $style_mode in $dock_style_modes {
         $is_shrink: str-index(#{$style_mode}, shrink) !=null;