Release 3.2.0

[kelson42]

• [x] Secure the CI is green on git master
• [x] Kiwix-Build is OK
• [x] Update the Changelog
• [x] Update version
• [x] Close current milestone and create new one incrementaly (a priori a minor version)
• [x] Create a tag on git
• [x] Secure new source/sbinaries are published on https://download.openzim.org/release/zim-tools/
• [x] Update the Github release with the Changelog
• [ ] Create new empty entry in Changelog (placeholder for future entries)
• [x] Publicize these new versions