Add merge queue tracking workflow #3

	# This workflow tracks when PRs are added ('enqueued') to the master branch merge queue, and when they are removed for
	# reasons other than 'MERGE', which means that it probably has to be enqueued again. The most common reason for this is
	# test failures when running the checks in the merge queue.
	name: Tracking Merge Queue
	on:
	pull_request:
	types: [ "enqueued", "dequeued" ]
	branches:
	- "master"

	permissions:
	id-token: write

	jobs:
	emit-enqueue:
	runs-on: ubuntu-latest
	if: ${{ github.repository == 'aws/aws-sdk-java-v2' && github.event.action == 'enqueued' }}

	steps:
	- name: Configure AWS Credentials
	uses: aws-actions/configure-aws-credentials@v1
	with:
	role-to-assume: ${{ secrets.CI_AWS_ROLE_ARN }}
	aws-region: us-west-2
	role-duration-seconds: 900
	- name: Record merge queue add
	run: \|
	aws --region us-west-2 cloudwatch put-metric-data --namespace AwsJavaSdkV2/GitHub --metric-name MergeQueue-Add --unit Count --value 1 --dimensions Branch=master

	emit-dequeue:
	runs-on: ubuntu-latest
	if: ${{ github.repository == 'aws/aws-sdk-java-v2' && github.event.action == 'dequeued' && github.event.reason != 'MERGE'}}
	steps:
	- name: Configure AWS Credentials
	uses: aws-actions/configure-aws-credentials@v1
	with:
	role-to-assume: ${{ secrets.CI_AWS_ROLE_ARN }}
	aws-region: us-west-2
	role-duration-seconds: 900
	- name: Record merge queue removal
	run: \|
	aws --region us-west-2 cloudwatch put-metric-data --namespace AwsJavaSdkV2/GitHub --metric-name MergeQueue-Remove --unit Count --value 1 --dimensions Branch=master

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