fix: tweak CSS and use same border color for both drop & button

Author: ghiscoding

packages/multiple-select-vanilla/src/styles/_variables.scss

@@ -38,7 +38,7 @@ $ms-choice-focus-border-color: lighten($ms-primary-color, 60%) !default;
 $ms-choice-focus-box-shadow: 0 0 0 1.5px rgba($ms-primary-color,.35) !default;
 $ms-drop-background: #fff !default;
 $ms-drop-color: #000 !default;
-$ms-drop-border: 1px solid #aaa !default;
+$ms-drop-border: 1px solid #d0d0d0 !default;
 $ms-drop-bottom-box-shadow: 0 4px 5px rgba(0, 0, 0, 0.15) !default;
 $ms-drop-top-box-shadow: 0 -4px 5px rgba(0, 0, 0, 0.15) !default;
 $ms-drop-border-radius: 4px !default;
@@ -93,7 +93,7 @@ $ms-search-padding: 4px !default;
 $ms-search-zindex: 10000 !default;
 $ms-search-icon-close-margin: 0 4px 0 7px !default;
 $ms-search-input-bg-color: #fff !default;
-$ms-search-input-border: 1px solid #aaa !default;
+$ms-search-input-border: 1px solid #b9b9b9 !default;
 $ms-search-input-border-radius: 5px !default;
 $ms-search-input-color: #444 !default;
 $ms-search-input-min-height: 24px !default;