snapcraft.yaml: install lensfun 0.3.2 from source

[whitty]

Install lensfun from source and run lensfun-update-data for more up to date data

Signed-off-by: Greg Whiteley greg.whiteley@gmail.com

This allowed access to some newer lens/camera selections. I don't know if this is how you would want to do this - you could instead:

• add a stage step which runs the update process.
• map /var/lib to somewhere in SNAP_USER_DATA, and run the update process at startup time (or periodically)

The reason for building from source was to also enable a potential followup to bump the version further: https://github.com/whitty/darktable-snap/commit/f8c09de03d22ca073e807df8548aad4490ce4549

[sergiusens]

Sorry for not noticing this one before moving trying to update the darktable snap to a newer version where I sort of did something similar, but also exposed a command to the snap to update the database from the CLI.

If you have future improvements, I will certainly look into them!