remove once_cell as dependency #62

Job	Run time
ci (ubuntu-latest, stable, arm-linux-androideabi)	27s
ci (ubuntu-latest, stable, armv7-linux-androideabi)	27s
ci (ubuntu-latest, stable, aarch64-linux-android)	30s
ci (ubuntu-latest, stable, i686-linux-android)	26s
ci (ubuntu-latest, beta, arm-linux-androideabi)	29s
ci (ubuntu-latest, beta, armv7-linux-androideabi)	27s
ci (ubuntu-latest, beta, aarch64-linux-android)	26s
ci (ubuntu-latest, beta, i686-linux-android)	26s
ci (ubuntu-latest, nightly, arm-linux-androideabi)	27s
ci (ubuntu-latest, nightly, armv7-linux-androideabi)	27s
ci (ubuntu-latest, nightly, aarch64-linux-android)	28s
ci (ubuntu-latest, nightly, i686-linux-android)	25s
ci (macOS-latest, stable, arm-linux-androideabi)	28s
ci (macOS-latest, stable, armv7-linux-androideabi)	27s
ci (macOS-latest, stable, aarch64-linux-android)	27s
ci (macOS-latest, stable, i686-linux-android)	26s
ci (macOS-latest, beta, arm-linux-androideabi)	27s
ci (macOS-latest, beta, armv7-linux-androideabi)	27s
ci (macOS-latest, beta, aarch64-linux-android)	29s
ci (macOS-latest, beta, i686-linux-android)	27s
ci (macOS-latest, nightly, arm-linux-androideabi)	30s
ci (macOS-latest, nightly, armv7-linux-androideabi)	44s
ci (macOS-latest, nightly, aarch64-linux-android)	27s
ci (macOS-latest, nightly, i686-linux-android)	27s
	11m 11s

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