Reasons for making this change:

Starting from version 1.5.0, Packer supports HCL2 definition files. These files serve the same purpose as Terraform .tfvars files, which persist variable values and are likely to contain sensitive data such as password, private keys, and other secrets.

Citation

We don't recommend saving usernames and password to version control, but you can create a local secret variables file and use -var-file to load it.

Links to documentation supporting these rule changes:

• https://www.packer.io/guides/hcl
• https://www.packer.io/guides/hcl/variables#from-a-file