chore: bump to v0.8.0 #16319

Job	Run time
Check typos and docs	6s
Clippy	3m 10s
Rustfmt	24s
Build GreptimeDB binaries (ubuntu-20.04)	4m 17s
Check (windows-2022)	6m 50s
Check (ubuntu-20.04)	1m 37s
Check License Header	1m 12s
Toml Check	19s
coverage	0s
Unstable Fuzz Test (unstable_fuzz_create_table_standalone)	13m 30s
Fuzz Test (fuzz_create_table)	5m 3s
Sqlness Test with Kafka Wal (ubuntu-20.04)	3m 8s
Fuzz Test (fuzz_alter_table)	4m 59s
Sqlness Test (ubuntu-20.04)	2m 29s
Fuzz Test (fuzz_create_database)	4m 55s
Fuzz Test (fuzz_create_logical_table)	4m 55s
Fuzz Test (fuzz_alter_logical_table)	4m 53s
Fuzz Test (fuzz_insert)	5m 17s
Fuzz Test (fuzz_insert_logical_table)	5m 11s
	1h 12m 15s

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