Release zcash_primitives version 0.20.0 #6079

Job	Run time
Bitrot check	1m 28s
Latest build on ubuntu-latest	1m 57s
Latest build on windows-latest	4m 49s
Latest build on macOS-latest	2m 14s
Build target wasm32-wasi	51s
Check ZFuture build on Linux	1m 47s
Clippy (beta)	15s
Check ZFuture build on macOS	1m 44s
Clippy (MSRV)	1m 20s
Check ZFuture build on Windows	6m 15s
Code coverage	1h 35m 50s
Intra-doc links	2m 10s
Rustfmt	16s
protobuf consistency	1m 5s
Test on Linux	6m 38s
UUID validity	11s
Test Orchard on Linux	8m 39s
Test NU7 on Linux	6m 56s
Test on macOS	8m 17s
Test Orchard on macOS	12m 11s
Test on Windows	13m 37s
Test Orchard on Windows	16m 55s
Test NU7 on Windows	12m 27s
Required status checks have passed	1s
	3h 27m 53s

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