add missing ext to building hours' local data

Author: hawkrives

source/views/building-hours/stateful-list.js

@@ -12,7 +12,7 @@ import {BuildingHoursList} from './list'
 import moment from 'moment-timezone'
 import type {TopLevelViewPropsType} from '../types'
 import type {BuildingType} from './types'
-import * as defaultData from '../../../docs/building-hours'
+import * as defaultData from '../../../docs/building-hours.json'
 import {reportNetworkProblem} from '../../lib/report-network-problem'
 import toPairs from 'lodash/toPairs'
 import groupBy from 'lodash/groupBy'