[Tech] Bump docker/build-push-action from 5 to 6 #30

Job	Run time
Build database upgrade image (buster, 11, 13, 2.3.1, 3.3.4, upgrade_pg.Dockerfile, pg11_to_pg13-t...	1m 58s
Build database upgrade image (bookworm, 13, 16, 2.14.2, 3.4.2, upgrade_pg.Dockerfile, pg13_to_pg1...	1m 43s
Build database image (11, 1.7.4, 2.5.5, pg11.Dockerfile, pg11-ts1.7.4-postgis2.5.5)	1m 32s
Build database image (11, 2.3.1, 3.3.4, pg11.Dockerfile, pg11-ts2.3.1-postgis3.3.4)	2m 17s
Build database image (13, 2.14.2, 3.4.2, pg13_16.Dockerfile, pg13-ts2.14.2-postgis3.4.2)	2m 49s
Build database image (16, 2.14.2, 3.4.2, pg13_16.Dockerfile, pg16-ts2.14.2-postgis3.4.2)	2m 48s
	13m 7s

Provide feedback