* 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
hcl2_upgrade transforms a JSON build-file in a HCL2 build-file.
This starts a validated Packer core and from that core we generate an HCL 'block' per plugin/configuration. So for a builder, a provisioner, a post-processor or a variable. The contents of each block is just transformed as is and basically all fields are HCL2-ified.
A generated field can be valid in JSON but invalid on HCL2; for example JSON templating (in mapstructure) allows to set arrays of strings - like `x = ["a", "b"]` - with single strings - like `x="a"` -, HCL does not allow this.
Since JSON does not make the distinction between variables and locals, everything will be a variable. So variables that use other variables will not work.
hcl2_upgrade tries to transform go templating interpolation calls to HCL2 calls when possible, leaving the go templating calls like they are in case it cannot.
Work:
* transpiler
* tests
* update hcl v2 library so that output looks great.
* update docs