Add support for openSUSE

I just tried this on openSUSE Tumbleweed:

$ sudo zypper ar https://download.docker.com/linux/fedora/docker-ce.repo

$ sudo sed -i 's/\$releasever/43/g' /etc/zypp/repos.d/docker-ce-*.repo

$ sudo zypper ref

# Install dependencies
$ sudo zypper in libseccomp2 libcgroup3

$ sudo zypper in docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
Loading repository data...
Reading installed packages...
Resolving package dependencies...
2 Problems:
Problem: 1: nothing provides 'libseccomp' needed by the to be installed containerd.io-2.2.1-1.fc43.x86_64
Problem: 2: nothing provides 'libcgroup' needed by the to be installed docker-ce-3:29.1.5-1.fc43.x86_64

Problem: 1: nothing provides 'libseccomp' needed by the to be installed containerd.io-2.2.1-1.fc43.x86_64
 Solution 1: do not install containerd.io-2.2.1-1.fc43.x86_64
 Solution 2: break containerd.io-2.2.1-1.fc43.x86_64 by ignoring some of its dependencies

Choose from above solutions by number or skip, retry or cancel [1/2/s/r/c/d/?] (c): 2

Problem: 2: nothing provides 'libcgroup' needed by the to be installed docker-ce-3:29.1.5-1.fc43.x86_64
 Solution 1: do not install docker-ce-3:29.1.5-1.fc43.x86_64
 Solution 2: break docker-ce-3:29.1.5-1.fc43.x86_64 by ignoring some of its dependencies

Choose from above solutions by number or skip, retry or cancel [1/2/s/r/c/d/?] (c): 2

$ sudo systemctl enable --now docker

I could run without issues. I will run the upstream tests on openQA to verify.

Any objections on using Fedora 43 as template for adding support for openSUSE? I think it would only be a matter of tweaking these 2 dependencies: libcgroup & libseccomp.

Review the existing Fedora 43 packaging template and the dependency declarations for libcgroup and libseccomp. Run the upstream tests on openQA for openSUSE; the work is done when the packages install without ignored dependencies and the tests pass.