update `halo2curves` to 0.6.0 #848

Job	Run time
Bitrot check	3m 7s
Intra-doc links	2m 11s
Build target wasm32-unknown-unknown	2m 21s
Rustfmt	14s
Build target wasm32-wasi	2m 16s
Test on ubuntu-latest with basic features	4m 43s
Test on windows-latest with basic features	6m 40s
Test on macOS-latest with basic features	8m 1s
Test on ubuntu-latest with all features	4m 59s
Test on windows-latest with all features	7m 15s
Test on macOS-latest with all features	9m 16s
	51m 3s

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