Builds seafile-client for Ubuntu 24.04 via docker.

Steps:

1. Clone this repository into a folder.
2. Within that folder run docker build --tag build-seafile-client ..
3. Then run mkdir data and docker run -v ./data:/data build-seafile-client.
4. The resulting .deb packages will be in data/.
5. To install them on your system run cd data && sudo dpkg -i *.deb and then sudo apt --fix-broken install.