update to pytorch 2.x, or >1.12 (for linux-aarch64 support)

tiara is currently pinned to pytorch 1.7, can it be updated? - current pytorch is v2.7.  The earliest pytorch supported on linux-aarch64 by conda-forge is 1.12, so even bumping to 1.12.0 would help.

does this just need trying / testing per the test instructions in README.md?

FYI - the README.md says python <= 3.8, but the conda-forge package for tiara is using python 3.9

