Add graph of librustzcash crate dependencies to README.md #6459

Job	Run time
Check ZFuture build on Linux	24s
Check ZFuture build on macOS	40s
Check ZFuture build on Windows	1m 43s
Test no-Orchard on Linux	4m 38s
Test Orchard on Linux	6m 24s
Test NU7 on Linux	6m 31s
Test no-Orchard on macOS	12m 17s
Bitrot check	1m 10s
Test Orchard on macOS	13m 31s
Test no-Orchard on Windows	9m 40s
Test Orchard on Windows	13m 57s
Test NU7 on Windows	13m 8s
Latest build on ubuntu-latest	55s
Latest build on windows-latest	3m 34s
Latest build on macOS-latest	1m 7s
Build target wasm32-wasi	58s
Build target thumbv7em-none-eabihf	43s
Clippy (MSRV)	1m 13s
Code coverage	1h 21m 48s
Clippy (beta)	12s
Intra-doc links	2m 9s
Slow Test Orchard on Linux	4m 15s
Slow Test NU7 on Linux	4m 11s
Rustfmt	15s
protobuf consistency	1m 5s
UUID validity	4s
Required status checks have passed	1s
	3h 6m 33s

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