Added capture prop

Added capture prop so this can be used with mobile camera e.g.

Open front camera on mobile
<picture-input capture="user" accept="image/*" />

Author: fatlinesofcode

PictureInput.vue

@@ -38,7 +38,7 @@
         <button v-if="removable" @click.prevent="removeImage" :class="removeButtonClass">{{ strings.remove }}</button>
       </div>
     </div>
-    <input ref="fileInput" type="file" :name="name" :id="id" :accept="accept" @change="onFileChange">
+    <input ref="fileInput" type="file" :name="name" :id="id" :accept="accept" @change="onFileChange" :capture="capture" />
   </div>
 </template>
 
@@ -62,6 +62,10 @@ export default {
       type: String,
       default: 'image/*'
     },
+    capture: {
+      type: String,
+      default: null
+    },
     size: {
       type: [String, Number],
       default: Number.MAX_SAFE_INTEGER