refactor: optimize backup metadata time format #404

	#
	# Licensed to the Apache Software Foundation (ASF) under one or more
	# contributor license agreements. See the NOTICE file distributed with
	# this work for additional information regarding copyright ownership.
	# The ASF licenses this file to You under the Apache License, Version 2.0
	# (the "License"); you may not use this file except in compliance with
	# the License. You may obtain a copy of the License at
	#
	# http://www.apache.org/licenses/LICENSE-2.0
	#
	# Unless required by applicable law or agreed to in writing, software
	# distributed under the License is distributed on an "AS IS" BASIS,
	# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	# See the License for the specific language governing permissions and
	# limitations under the License.
	#

	name: Unit Test

	on:
	pull_request:
	branches: [ main ]
	paths:
	- 'shardingsphere-operator/**'
	- 'pitr/**'
	- '.github/workflows/unit-test.yml'
	jobs:
	operator:
	runs-on: ubuntu-latest
	steps:
	- name: "checkout codes"
	uses: actions/checkout@v3
	- name: "setup go"
	uses: actions/setup-go@v4
	with:
	go-version: '^1.18.1'
	- name: "shardingsphere operator test"
	run: \|
	cd shardingsphere-operator
	make test
	- name: "pitr agent test"
	run: \|
	cd pitr/agent
	make test
	- name: "pitr cli test"
	run: \|
	cd pitr/cli
	make test
	- name: "aggregate reports"
	run: \|
	cat ./shardingsphere-operator/cover.out >> cover.out
	cat ./pitr/cli/cover.out >> cover.out
	cat ./pitr/agent/cover.out >> cover.out
	- name: "code coverage"
	uses: codecov/codecov-action@v3
	with:
	files: ./cover.out

Provide feedback