Fixed useless px modifier on default

Author: issayah

src/components/BPopover.vue

@@ -64,7 +64,7 @@ export default defineComponent({
     variant: {type: String as PropType<ColorVariant>, default: undefined},
     html: {type: Boolean, default: true},
     sanitize: {type: Boolean, default: false},
-    offset: {type: String as PropType<Popover.Options['offset']>, default: '0px'},
+    offset: {type: String as PropType<Popover.Options['offset']>, default: '0'},
   },
   emits: ['show', 'shown', 'hide', 'hidden', 'inserted'],
   setup(props, {emit, slots}) {