fix 'Always last available' for pillow version

[SimonFischer04]

'Always last available' did not actually use latest version, but some fixed version before.

Not sure if it's better to include this or not.
CI fails with:

The conflict is caused by:
    The user requested pillow==12.2.0
    esphome 2026.3.2 depends on pillow==12.1.1

So newest esphome does not work with newest pillow ...
But sometimes newer esphome versions require newer pillow versions ...

Maybe better to manually change pillow version every few times a new esphome releases, until this should be improved with idea outlined in:
#183