Doc: add change-log 0.9.16 #4040

Job	Run time
openraft-features (nightly, generic-snapshot-data)	54s
cluster-benchmark (cluster_benchmark)	51s
examples (stable, memstore)	53s
examples (stable, raft-kv-memstore)	2m 33s
examples (stable, raft-kv-memstore-generic-snapshot-data)	56s
examples (stable, raft-kv-memstore-opendal-snapshot-data)	1m 10s
examples (stable, raft-kv-memstore-singlethreaded)	58s
examples (stable, raft-kv-rocksdb)	8m 10s
examples (nightly, memstore)	59s
external-stores (stores/rocksstore-v2)	6m 17s
examples (nightly, raft-kv-memstore)	2m 16s
examples (nightly, raft-kv-memstore-generic-snapshot-data)	1m 20s
examples (nightly, raft-kv-memstore-opendal-snapshot-data)	1m 24s
lint	11m 36s
examples (nightly, raft-kv-memstore-singlethreaded)	1m 9s
examples (nightly, raft-kv-rocksdb)	12m 37s
openraft-feature-test (nightly)	53s
openraft-feature-test (nightly, serde)	53s
openraft-test (stable, 0)	3m 24s
openraft-feature-test (nightly, single-term-leader)	52s
openraft-test (nightly, 30)	3m 24s
openraft-feature-test (nightly, single-term-leader,serde,singlethreaded)	55s
openraft-test (nightly, 0, single-term-leader)	3m 15s
openraft-test-bench (nightly)	1m 4s
stores (memstore)	1m 0s
Build (nightly, bench,serde,bt,singlethreaded)	52s
stores (rocksstore)	6m 4s
stores (sledstore)	1m 17s
tests-feature-test (nightly)	2m 53s
tests-feature-test (nightly, single-term-leader)	2m 58s
tests-feature-test (nightly, loosen-follower-log-revert)	2m 56s
	1h 26m 43s

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