Merge pull request #443 from zcash/pczt-verifier #3270

Job	Run time
Build target wasm32-wasi	1m 30s
Latest build on ubuntu-latest	51s
Latest build on windows-latest	2m 50s
Bitrot check	2m 5s
Latest build on macOS-latest	57s
Test on ubuntu-latest	9m 57s
Book tests	16s
Test on windows-latest	11m 24s
Test on macOS-latest	8m 46s
Code coverage	9m 6s
Intra-doc links	2m 19s
Rustfmt	13s
	50m 14s

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