add git and hg to docker image

[bobcallaway]

When running the action against terraform containing modules sourced over git, the action would fail with the following message:

Example Terraform:

module "sigstore" {
  source = "git::https://github.com/sigstore/scaffolding.git//terraform/gcp/modules/sigstore?ref=130f8b87521ef67bf03486166385c36fff49ba4a"
  ...

Log message from tfsec-sarif-action:

terraform.parser.<root>.evaluator Failed to load module 'failed to download: error downloading 'https://github.com/sigstore/scaffolding.git?ref=130f8b87521ef67bf03486166385c36fff49ba4a': git must be available and on the PATH'. Maybe try 'terraform init'?

This commit adds the git and hg binaries to the underlying base image to ensure that the full module content is fetched and analyzed.

Signed-off-by: Bob Callaway bob.callaway@gmail.com

[owenrumney]

LGTM, thanks