Add graph of librustzcash crate dependencies to README.md #6467

Job	Run time
Latest build on ubuntu-latest	57s
Latest build on windows-latest	3m 58s
Latest build on macOS-latest	1m 2s
Check ZFuture build on Linux	23s
Check ZFuture build on macOS	28s
Test no-Orchard on Linux	4m 33s
Check ZFuture build on Windows	6m 1s
Test Orchard on Linux	6m 22s
Test NU7 on Linux	6m 33s
Test no-Orchard on macOS	6m 27s
Test Orchard on macOS	7m 56s
Slow Test Orchard on Linux	4m 20s
Test no-Orchard on Windows	7m 53s
Bitrot check	1m 10s
Slow Test NU7 on Linux	4m 13s
Build target wasm32-wasi	1m 0s
Test Orchard on Windows	13m 55s
Test NU7 on Windows	11m 54s
Build target thumbv7em-none-eabihf	39s
Clippy (MSRV)	1m 17s
Clippy (beta)	12s
Code coverage	1h 17m 1s
Intra-doc links	2m 14s
protobuf consistency	1m 1s
Rustfmt	15s
UUID validity	4s
Required status checks have passed	1s
	2h 51m 49s

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