readme: fix dead link #2813

Job	Run time
openraft-test-bench (nightly)	52s
openraft-test (stable, 0)	2m 48s
openraft-test (nightly, 30)	3m 15s
openraft-test (nightly, 0, single-term-leader)	2m 53s
Build (nightly, bench,serde,bt,singlethreaded)	49s
cluster-benchmark (cluster_benchmark)	49s
external-stores (stores/rocksstore-v2)	6m 11s
examples (stable, raft-kv-memstore)	2m 8s
examples (stable, raft-kv-rocksdb)	6m 41s
examples (nightly, raft-kv-memstore)	2m 10s
lint	6m 36s
examples (nightly, raft-kv-rocksdb)	11m 57s
openraft-feature-test (nightly)	50s
openraft-feature-test (nightly, serde)	53s
stores (memstore)	45s
openraft-feature-test (nightly, single-term-leader)	49s
tests-feature-test (nightly)	2m 42s
stores (rocksstore)	5m 56s
openraft-feature-test (nightly, single-term-leader,serde,singlethreaded)	53s
stores (rocksstore-compat07)	6m 5s
tests-feature-test (nightly, single-term-leader)	2m 43s
stores (sledstore)	59s
tests-feature-test (nightly, loosen-follower-log-revert)	2m 41s
	1h 12m 25s

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