Update oras.land/oras-go and remove replaces #57

	name: Continuous Integration
	on:
	pull_request:
	types: [opened, synchronize, reopened]
	push:
	branches:
	- master

	jobs:
	report:
	name: Report
	runs-on: ubuntu-latest
	steps:
	- name: ref
	run: echo ${{ github.ref }}
	- name: event_name
	run: echo ${{ github.event_name }}
	build:
	name: Build
	runs-on: ubuntu-latest
	steps:
	- name: checkout
	uses: actions/checkout@v2
	- uses: actions/setup-go@v2
	with:
	go-version: '1.15.4'
	- name: lint
	uses: golangci/golangci-lint-action@v2
	- name: vet
	run: make vet
	- name: test
	run: make test
	- name: fmt
	run: make fmt-check
	- name: build
	run: make build

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