Install Docker from official repository for newer API version

The docker.io package from apt provides Docker client API v1.41,
which is too old for the DIND server (requires v1.44+).

Install docker-ce-cli from Docker's official repository to get
a compatible client version.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.forgejo/workflows/docker-build.yml

@@ -16,7 +16,15 @@ jobs:
       - name: Set up Docker
         run: |
           echo "DOCKER_HOST: ${DOCKER_HOST}"
-          apt-get update -qq && apt-get install -y -qq docker.io
+          # Install Docker from official repository to get newer version
+          apt-get update -qq
+          apt-get install -y -qq ca-certificates curl
+          install -m 0755 -d /etc/apt/keyrings
+          curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
+          chmod a+r /etc/apt/keyrings/docker.asc
+          echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | tee /etc/apt/sources.list.d/docker.list > /dev/null
+          apt-get update -qq
+          apt-get install -y -qq docker-ce-cli
           docker version
 
       - name: Checkout repository