build-helm-charts: Fix --package option parsing

When building helm charts, it has been observed that the preferred long
option for specifying packages, `--package`, isn't being recognized by
`getopt` as a valid option.

As a result, one must resort to the deprecated alternative `--rpm`.

Therefore, this change adds `package` as one of the long options for
`getopt`. And since it updates the parameters of this build script, it
also updates the help message of the `--os` parameter to match the other
scripts:

  * build-wheels/build-wheel-tarball.sh;
  * build-docker-images/build-stx-base.sh;
  * build-docker-images/build-stx-images.

Test Plan:
PASS - Build helm charts with --rpm
PASS - Build helm charts with --package

Closes-Bug: 2022090

Change-Id: Ia45930d30e99ceb15d2f0753519cd8290fcaa446
Signed-off-by: Luan Nunes Utimura <LuanNunes.Utimura@windriver.com>

build-tools/build-helm-charts.sh

@@ -39,7 +39,7 @@ $(basename $0) [--os <os>] [-a, --app <app-name>]
                [-p, --patch-dependency <patch-dependency>] [ --verbose ]
 Options:
     --os:
-            Specify base OS (eg. centos)
+            Specify base OS (valid options: ${SUPPORTED_OS_ARGS[@]})
 
     -a, --app NAME:
             Specify the application name
@@ -679,7 +679,7 @@ function get_app_version {
 }
 
 # TODO(awang): remove the deprecated image-file option
-OPTS=$(getopt -o h,a:,A:,B:,r:,i:,l:,p: -l help,os:,app:,app-version-file:,app-version:,rpm:,image-record:,image-file:,label:,patch-dependency:,verbose -- "$@")
+OPTS=$(getopt -o h,a:,A:,B:,r:,i:,l:,p: -l help,os:,app:,app-version-file:,app-version:,rpm:,package:,image-record:,image-file:,label:,patch-dependency:,verbose -- "$@")
 if [ $? -ne 0 ]; then
     usage
     exit 1