Bump hashbrown from 0.15.1 to 0.15.2 #467

Job	Run time
rust_ci (macos-latest, stable)	59s
rust_ci (macos-latest, beta)	1m 32s
rust_ci (macos-latest, nightly)	2m 29s
rust_ci (ubuntu-latest, stable)	1m 3s
rust_ci (ubuntu-latest, beta)	1m 6s
rust_ci (ubuntu-latest, nightly)	1m 36s
rust_ci (windows-latest, stable)	2m 53s
rust_ci (windows-latest, beta)	2m 38s
rust_ci (windows-latest, nightly)	3m 18s
	17m 34s

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