* Update ubuntu-latest tag to ubuntu-22.04
Everytime a CI service such a GitHub actions update the images
corresponding to their 'latest' tags, pipelines tend to have some
hipcups due to changes in the distribution default packages.
By fixing the images to a specific one, we should be more resilient to
changes in the Github actions environment.
* Use same build directory used in CMake presets
Additional interesting changes in this commit:
- conan: use cmake-conan for better CMake-Conan integration
- cmake+doc: Remove deprecated EXIV2_ENABLE_WIN_UNICODE
- Ignore CMakeUserPresets.json
- doc: Add notes about the usage of CMake presets
Sometime the nightly pre-release would be in "draft" status on github.
It's hard to reproduce but I had the guess that maybe the deletion of
old tag and release on the github side wasn't quite done when the
new release was being created. Of course only speculation...
But, moving the download of the artifacts in betweent these two steps
seems to have fixed the symptom.
