refactor: replace map-values() with map.values()

Author: mrholek

scss/functions/_assert.scss

@@ -1,4 +1,5 @@
 @use "sass:list";
+@use "sass:map";
 @use "sass:math";
 
 // Ascending
@@ -23,7 +24,7 @@
 // Used to ensure the min-width of the lowest breakpoint starts at 0.
 @mixin assert-starts-at-zero($map, $map-name: "$grid-breakpoints") {
   @if length($map) > 0 {
-    $values: map-values($map);
+    $values: map.values($map);
     $first-value: list.nth($values, 1);
     @if $first-value != 0 {
       @warn "First breakpoint in #{$map-name} must start at 0, but starts at #{$first-value}.";