feat: add debug

- Adds `--help` / `-h` option to `./build.sh` for help.
- Adds `--debug` / `-d` option to `./build.sh` for debug mode.

Ref: #697

Signed-off-by: Ryan Johnson <johnsonryan@vmware.com>

CHANGELOG.md

@@ -20,6 +20,7 @@
 - Adds an example `.gitlab.yml` file for GitLab CI/CD. [GH-675](https://github.com/vmware-samples/packer-examples-for-vsphere/pull/675)
 - Adds a `build-ci.tmpl` that can be used to create or update the `.gitlab-ci.yml` file using gomplate. [GH-675](https://github.com/vmware-samples/packer-examples-for-vsphere/pull/675)
 - Adds Packer logging settings to `set-envvars.sh`. [GH-705](https://github.com/vmware-samples/packer-examples-for-vsphere/pull/705)
+- Adds a debug option (`--debug` or `-d`) to`./build.sh` to enable debug logging for Packer. [GH-706](https://github.com/vmware-samples/packer-examples-for-vsphere/pull/706)
 
 :bug: **Bugfix**: