S. Riette 29 sept 2022: change reference to use 48t3 instead of 48t1

In the previsous commit the physics modifications between cy48t1 and cy48t3
have been introduced in PHYEX but still using the cy48t1 pack.
This commit introduces new modifications (in arome/ext) to use the cy48t3 pack.
Results are different due to modifications introduced betwwen cy48t1 and cy48t3
in parts other than the physics.
So, a new reference is needed (modifications in check_commit_ial.sh, INSTALL_pack_ial.md).