fix(MdStep): set tabindex for not active step

Author: Samuell1

src/components/MdSteppers/MdStep.vue

@@ -2,7 +2,7 @@
   <div class="md-stepper">
     <md-step-header v-if="MdSteppers.isVertical" :index="id" />
 
-    <div class="md-stepper-content" :class="{ 'md-active': !MdSteppers.syncRoute && id === MdSteppers.activeStep }">
+    <div :class="['md-stepper-content', { 'md-active': id === MdSteppers.activeStep }]" :tabindex="tabIndex">
       <slot />
     </div>
   </div>
@@ -43,6 +43,13 @@
         }
       }
     },
+    computed: {
+      tabIndex () {
+        return this.id !== this.MdSteppers.activeStep
+        ? -1
+        : false
+      }
+    },
     methods: {
       getPropValues () {
         const propNames = Object.keys(this.$options.props)