[improvement] update color variables (#2010)

packages/number-keyboard/index.vue

@@ -28,7 +28,7 @@
       </div>
       <div v-if="theme === 'custom'" :class="b('sidebar')">
         <key :text="'delete'" :type="['delete', 'big']" @press="onPressKey" />
-        <key :text="closeButtonText" :type="['green', 'big']" @press="onPressKey" />
+        <key :text="closeButtonText" :type="['blue', 'big']" @press="onPressKey" />
       </div>
     </div>
   </transition>

packages/number-keyboard/test/__snapshots__/demo.spec.js.snap

@@ -46,7 +46,7 @@ exports[`renders demo correctly 1`] = `
       </div>
       <div class="van-number-keyboard__sidebar">
         <i class="van-hairline van-key van-key van-key--delete van-key van-key--big">delete</i>
-        <i class="van-hairline van-key van-key van-key--green van-key van-key--big">完成</i>
+        <i class="van-hairline van-key van-key van-key--blue van-key van-key--big">完成</i>
       </div>
     </div>
   </div>