requirements: update matplotlib requirement from <3.7.6 to <3.9.5 #9882

Job	Run time
build (3.7, x64, ubuntu)	57m 29s
build (3.7, x64, windows)	53m 36s
build (3.11, x64, ubuntu)	1h 24m 23s
build (3.11, x64, macos)	27m 7s
build (3.11, x64, windows)	1h 25m 56s
build (3.12, x64, ubuntu)	1h 23m 16s
build (3.12, x64, macos)	30m 1s
build (3.12, x64, windows)	1h 23m 19s
build (3.9, macos, --cov=psyneulink)	43m 25s
build (3.9, ubuntu, --forked -m "not llvm")	35m 31s
build (3.8, x86, windows)	1h 30m 40s
build (3.10, ubuntu, --fp-precision=fp32)	1h 26m 29s
build (3.10, macos, -m benchmark --benchmark-enable --benchmark-only --benchmark-min-rounds=2 --b...	32m 26s
build (3.7, x64, ubuntu, min)	57m 3s
build (3.8, macos)	32m 56s
	14h 43m 37s

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