Log Message:
update graphics/darktable to 2.2.5.

From the changelog against 2.2.4:

## New features:

- When appending EXIF data to an exported image, do not fail if reading of EXIF \ 
from the original file fails
- Support XYZ as proofing profile
- Clear DerivedFrom from XMP before writing it
- bauhaus: when using soft bounds, keep slider step constant

## Bugfixes:

- Some GCC7 build fixes
- cmstest: fix crash when missing XRandR extension.
- Fix crash in Lua libs when collapsing libs
- Mac packaging: some fixes
- RawSpeed: TiffIFD: avoid double-free
- Fix a few alloc-dealloc mismatches

## Base Support:

- Canon EOS 77D
- Canon EOS 9000D
- Nikon D500 (14bit-uncompressed, 12bit-uncompressed)
- Nikon D5600 (12bit-compressed, 12bit-uncompressed, 14bit-compressed, \ 
14bit-uncompressed)
- Panasonic DC-FZ82 (4:3)
- Panasonic DMC-FZ80 (4:3)
- Panasonic DMC-FZ85 (4:3)
- Panasonic DC-GH5 (4:3)

## White Balance Presets:

- Pentax K-3 II

## Noise Profiles:

- Nikon D500
- Panasonic DMC-FZ300
- Panasonic DMC-LX100
- Pentax K-70
- Sony ILCE-5000