Add option to specify container CPU platform

Signed-off-by: Andrew Bobulsky <rulerof@gmail.com>

README.md

@@ -596,6 +596,20 @@ Examples:
   use_internal_docker_network: true
 ```
 
+### docker_platform
+
+Configure the CPU platform (architecture) used by docker to build the image.
+
+Examples:
+
+```yaml
+  docker_platform: linux/arm64
+```
+
+```yaml
+  docker_platform: linux/amd64
+```
+
 ## Development
 
 * Source hosted at [GitHub][repo]

lib/kitchen/docker/helpers/cli_helper.rb

@@ -84,6 +84,7 @@ def build_run_command(image_id, transport_port = nil)
           Array(config[:cap_add]).each { |cap| cmd << " --cap-add=#{cap}"} if config[:cap_add]
           Array(config[:cap_drop]).each { |cap| cmd << " --cap-drop=#{cap}"} if config[:cap_drop]
           Array(config[:security_opt]).each { |opt| cmd << " --security-opt=#{opt}"} if config[:security_opt]
+          cmd << " --platform=#{config[:docker_platform]}" if config[:docker_platform]
           extra_run_options = config_to_options(config[:run_options])
           cmd << " #{extra_run_options}" unless extra_run_options.empty?
           cmd << " #{image_id} #{config[:run_command]}"

lib/kitchen/docker/helpers/image_helper.rb

@@ -46,6 +46,7 @@ def remove_image(state)
         def build_image(state, dockerfile)
           cmd = 'build'
           cmd << ' --no-cache' unless config[:use_cache]
+          cmd << " --platform=#{config[:docker_platform]}" if config[:docker_platform]
           extra_build_options = config_to_options(config[:build_options])
           cmd << " #{extra_build_options}" unless extra_build_options.empty?
           dockerfile_contents = dockerfile