build-helm-charts: getopt: unrecognized option '--package'

[Luan Nunes Utimura]

Brief Description
-----------------
When trying to build helm charts with the --package option instead of the deprecated --rpm, one gets a message saying that the parameter is not recognized by getopt.

Severity
--------
Minor.

Steps to Reproduce
------------------
In a build environment, try building the stx-openstack helm charts:

$ ./build-helm-charts.sh --verbose --os debian --app stx-openstack \
    --package stx-openstack-helm-fluxcd --image-record /path/to/image-record.lst

Expected Behavior
------------------
Helm charts are built successfully and the application tarball is generated.

Actual Behavior
----------------
Helm charts can't be built due to an option parsing error.

Reproducibility
---------------
Reproducible.

System Configuration
--------------------
Debian.

Branch/Pull Time/Commit
-----------------------
Branch `master`.

Last Pass
---------
N/A.

Timestamp/Logs
--------------
```
./build-helm-charts.sh --verbose --os debian --app stx-openstack --package stx-openstack-helm-fluxcd --image-record /localdisk/images-debian-stable-latest.lst
getopt: unrecognized option '--package'
Usage:
build-helm-charts.sh [--os <os>] [-a, --app <app-name>]
               [-A, --app-version-file /path/to/helm-charts-release-info.inc]
               [-B, --app-version <version>]
               [-r, --rpm <rpm-name>] [-i, --image-record <image-record>] [--label <label>]
               [-p, --patch-dependency <patch-dependency>] [ --verbose ]
[...]
```

Test Activity
-------------
Developer Testing.

Workaround
----------
Use the deprecated option --rpm (or -r) instead of --package.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/starlingx/root/+/885086