Downgrade Docker on GHA.

.github/workflows/nox.yml

@@ -31,5 +31,28 @@ jobs:
       upload-codecov-push: false
       upload-codecov-schedule: true
       max-ansible-core: "2.17"
+      # For some reason GitHub decided to bump Docker on the ubuntu-24.04 image,
+      # which is not compatible with podman and various other things.
+      pre-test-cmd-integration: |-
+        # See https://docs.docker.com/engine/install/ubuntu/.
+
+        # Add Docker's official GPG key:
+        sudo apt update
+        sudo apt install ca-certificates curl
+        sudo install -m 0755 -d /etc/apt/keyrings
+        sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
+        sudo chmod a+r /etc/apt/keyrings/docker.asc
+
+        # Add the repository to Apt sources:
+        sudo tee /etc/apt/sources.list.d/docker.sources <<EOF
+        Types: deb
+        URIs: https://download.docker.com/linux/ubuntu
+        Suites: $(. /etc/os-release && echo "${UBUNTU_CODENAME:-$VERSION_CODENAME}")
+        Components: stable
+        Signed-By: /etc/apt/keyrings/docker.asc
+        EOF
+
+        sudo apt update
+        sudo apt-get install -y --allow-downgrades docker-ce-cli=5:28.0.4-1~ubuntu.24.04~noble docker-ce=5:28.0.4-1~ubuntu.24.04~noble
     secrets:
       CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}