Fix install-docker.sh to support ARM64 architecture

The script was hardcoded to download x86_64 Docker binaries, causing
"Exec format error" on ARM64 runners. This commit adds architecture
detection to download the appropriate binaries for both amd64 and arm64.

Changes:
- Add architecture detection using uname -m
- Map system architecture to Docker download paths (x86_64/aarch64)
- Map architecture to buildx binary names (amd64/arm64)
- Add informative echo to show detected architecture
- Add error handling for unsupported architectures

This fix is required for ARM64 integration tests to run successfully.

Signed-off-by: thc1006 <84045975+thc1006@users.noreply.github.com>

Author: thc1006

.github/workflows/scripts/install-docker.sh

@@ -2,10 +2,30 @@
 
 set -x
 VER="28.0.4"
-curl -L -o /tmp/docker-$VER.tgz https://download.docker.com/linux/static/stable/x86_64/docker-$VER.tgz
+
+# Detect architecture
+ARCH=$(uname -m)
+case $ARCH in
+  x86_64)
+    DOCKER_ARCH="x86_64"
+    BUILDX_ARCH="amd64"
+    ;;
+  aarch64)
+    DOCKER_ARCH="aarch64"
+    BUILDX_ARCH="arm64"
+    ;;
+  *)
+    echo "Unsupported architecture: $ARCH"
+    exit 1
+    ;;
+esac
+
+echo "Installing Docker $VER for architecture: $ARCH (docker: $DOCKER_ARCH, buildx: $BUILDX_ARCH)"
+
+curl -L -o /tmp/docker-$VER.tgz https://download.docker.com/linux/static/stable/$DOCKER_ARCH/docker-$VER.tgz
 tar -xz -C /tmp -f /tmp/docker-$VER.tgz
 mkdir -vp ~/.docker/cli-plugins/
-curl --silent -L "https://github.com/docker/buildx/releases/download/v0.3.0/buildx-v0.3.0.linux-amd64" > ~/.docker/cli-plugins/docker-buildx
+curl --silent -L "https://github.com/docker/buildx/releases/download/v0.3.0/buildx-v0.3.0.linux-$BUILDX_ARCH" > ~/.docker/cli-plugins/docker-buildx
 chmod a+x ~/.docker/cli-plugins/docker-buildx
 mv /tmp/docker/* /usr/bin
 docker run --privileged --rm tonistiigi/binfmt --install all