Update release notes of v2.9 #299

Job	Run time
Tests on other platforms (windows-2019, 3.10)	3m 0s
Tox test (py38)	1m 54s
Tests on paywalled platforms	0s
Tests on other platforms (windows-2022, 3.11)	2m 24s
Tox test (py39)	1m 52s
Tests on other platforms (windows-2022, 3.12)	2m 18s
Tox test (py310)	1m 50s
Tests on other platforms (macos-12, 3.11)	1m 31s
Tox test (py311)	2m 9s
Tests on other platforms (macos-13, 3.12)	1m 39s
Tox test (py312-cover)	2m 39s
Tox test (docs, graphviz)	1m 47s
Docker image	0s
PyPI packaging	0s
	23m 3s

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