Add a little hint to README-dev.md #2919

Job	Run time
Build-And-Test-Web	5m 5s
Build-And-Test-Server (Simple integration tests)	13m 16s
Build-And-Test-Server (DEX integration tests)	11m 37s
Build-And-Test-Server (DEX integration test with proofs)	11m 15s
Build-And-Test-Server (Voting integration tests)	5m 21s
Build-And-Test-Server (Unit tests)	35m 34s
Build-And-Test-Server (Verification Key Regression Check)	7m 21s
Build-And-Test-Server (CommonJS test)	2m 26s
Release-mina-signer-on-NPM	1m 12s
Release-on-NPM	1m 38s
	1h 34m 45s

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