Detect if user supplied a valid protobuf bundle #5816

	#
	# Copyright 2024 The Sigstore Authors.
	#
	# Licensed 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: Do Not Submit

	on:
	pull_request:
	branches:
	- 'main'
	- 'release-*'

	permissions: {}

	jobs:
	donotsubmit:
	name: Do Not Submit
	runs-on: ubuntu-latest

	if: github.repository == 'sigstore/cosign'

	permissions:
	contents: read

	steps:
	- name: Check out code
	uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 #v2.4.0

	- name: Do Not Submit
	uses: chainguard-dev/actions/donotsubmit@84c993eaf02da1c325854fb272a4df9184bd80fc # main

Provide feedback