add support for selecting Packer version

[ksatirli]

Different use cases might call for an older (or newer) Packer version than is currently hardcoded in the Action.

The Packer version should be user-defined.

[ruimoreira]

Could this not be achieved by having different releases, with tags that match the version of packer in the Dockerfile ? For example I submitted a PR to update to 1.7.3 this could be release as @1.7.3 and users could reference this action like this uses: hashicorp/[email protected]

Thoughts ?

[anitakrueger]

Is there any update on this? I have a required_version parameter in my packer.hcl and for 1.8.0 and 1.7.10 the run fails with:

Error: Unsupported Packer Core version

  on packer/packer.pkr.hcl line 2, in packer:
   2:   required_version = ">= 1.7.[10]"

[anitakrueger]

I didn't see a supported version in the README either unfortunartely. I do see from the last commit now that we need to use 1.7.8.