* start using `go:generate packer-sdc struct-markdown`
* Update Makefile
remove @go install ./cmd/struct-markdown
* run go generate for struct-markdown
* use //go:generate packer-sdc mapstructure-to-hcl2
* run go generate for mapstructure-to-hcl2
* remove struct-markdown and mapstructure-to-hcl2
* vendor vendors
