add php84 support #4072

Job	Run time
mariadb (locked, 8.3, ubuntu-latest, 10.5)	1m 26s
mariadb (locked, 8.3, ubuntu-latest, 10.6)	1m 28s
mariadb (locked, 8.3, ubuntu-latest, 10.11)	1m 20s
mariadb (locked, 8.3, ubuntu-latest, 11.1)	1m 3s
mariadb (locked, 8.3, ubuntu-latest, 11.4)	1m 30s
mysql (locked, 8.3, ubuntu-latest, 5.7)	58s
mysql (locked, 8.3, ubuntu-latest, 8.0)	1m 31s
mysql (locked, 8.3, ubuntu-latest, 8.4)	56s
mysql (locked, 8.3, ubuntu-latest, 9.0)	1m 24s
Postgres (locked, 8.3, ubuntu-latest, 12.20)	1m 32s
Postgres (locked, 8.3, ubuntu-latest, 13.16)	1m 30s
Postgres (locked, 8.3, ubuntu-latest, 14.13)	58s
Postgres (locked, 8.3, ubuntu-latest, 15.8)	1m 26s
Postgres (locked, 8.3, ubuntu-latest, 16.4)	1m 4s
Postgres (locked, 8.3, ubuntu-latest, 17.0)	56s
Sqlite (locked, 8.3, ubuntu-latest)	15s
	19m 17s

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