Add changelog for Mergify addition #1312

Job	Run time
Self-Check	11s
Run tests on ubuntu-latest, py3.8	1m 8s
Run tests on ubuntu-latest, py3.9	1m 7s
test-sdist	1m 38s
Run tests on ubuntu-latest, py3.10	1m 1s
ensure-catalog-matches-hook-config	22s
Run tests on ubuntu-latest, py3.11	1m 5s
Run 'mypy' on python 3.x	23s
Run 'twine-check' on python 3.x	21s
Run tests on ubuntu-latest, py3.12	1m 10s
Run 'py-mindeps' on python 3.8	28s
Run tests on windows-latest, py3.8	2m 23s
Run tests on windows-latest, py3.9	2m 24s
Run tests on windows-latest, py3.10	1m 48s
Run tests on windows-latest, py3.11	1m 39s
Run tests on windows-latest, py3.12	2m 23s
Run tests on macos-latest, py3.8	1m 33s
Run tests on macos-latest, py3.9	1m 7s
Run tests on macos-latest, py3.10	45s
Run tests on macos-latest, py3.11	42s
Run tests on macos-latest, py3.12	59s
Collate results to check for skipped tests	8s
	24m 45s

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