Update to latest tooling image version (v.1.4.0)

The actions are pointing to the [v1.3.2](https://github.com/hashicorp/tfc-workflows-tooling/releases/tag/v1.3.2), but the latest release is the [v.1.4.0](https://github.com/hashicorp/tfc-workflows-tooling/releases/tag/v1.4.0):

https://github.com/search?q=repo%3Ahashicorp%2Ftfc-workflows-github%20hashicorp%2Ftfci&type=code

Thanks!