Table: added scss variable $--table-border-color (#10179)

packages/table/package.json

 {
   "name": "element-table",
-  "version": "2.0.0",
+  "version": "2.2.2",
   "description": "A table component for Vue.",
   "keywords": [
     "element",

packages/theme-chalk/src/common/var.scss

@@ -475,7 +475,8 @@ $--dialog-padding-primary: 20px !default;
 
 /* Table
 -------------------------- */
-$--table-border:  1px solid $--border-color-lighter !default;
+$--table-border-color: $--border-color-lighter !default;
+$--table-border: 1px solid $--table-border-color !default;
 $--table-text-color: $--color-text-regular !default;
 $--table-header-color: $--color-text-secondary !default;
 $--table-row-hover-background: $--background-color-base !default;

packages/theme-chalk/src/table.scss

@@ -253,7 +253,7 @@
     @include share-rule(border-pseudo) {
       content: '';
       position: absolute;
-      background-color: $--border-color-lighter;
+      background-color: $--table-border-color;
       z-index: 1;
     }