Bump for Beta 21 RC5 #1594

Job	Run time
check	3m 9s
test	11m 49s
clippy	3m 52s
rustfmt	4s
audit	25s
cross-aarch64	1m 25s
cross-armv7	1m 23s
integration-test-five-nodes	12m 52s
integration-test-eth-payments	14m 35s
integration-test-debts	17m 3s
integration-test-db-migration	12m 23s
integration-test-althea-payment	17m 46s
integration-test-validate-contract	12m 24s
integration-test-multi-exit	13m 18s
	2h 2m 28s

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