set BuildTag for Dockerfile and Chart.yaml using push-packages-to-obs.sh

[cbosdo]

What does this PR change?

helm enforces semverv2 on the image tags on OCI repositories. This means that we need one to pull the chart from the repository generated by OBS. For the testsuite we need to add the semantic version as tag on Helm Charts only.

GUI diff

No difference.

• DONE

Documentation

• No documentation needed: only internal and user invisible changes

• DONE

Test coverage

• No tests: proxy images additional tags removed

• DONE

Links

Fixes #
Tracks # add downstream PR, if any

• DONE

Changelogs

Make sure the changelogs entries you are adding are compliant with https://github.com/uyuni-project/uyuni/wiki/Contributing#changelogs and https://github.com/uyuni-project/uyuni/wiki/Contributing#uyuni-projectuyuni-repository

If you don't need a changelog check, please mark this checkbox:

• No changelog needed

If you uncheck the checkbox after the PR is created, you will need to re-run changelog_test (see below)

Re-run a test

If you need to re-run a test, please mark the related checkbox, it will be unchecked automatically once it has re-run:

• Re-run test "changelog_test"
• Re-run test "backend_unittests_pgsql"
• Re-run test "java_pgsql_tests"
• Re-run test "schema_migration_test_pgsql"
• Re-run test "susemanager_unittests"
• Re-run test "javascript_lint"
• Re-run test "spacecmd_unittests"

[deneb-alpha]

LGTM, thanks

[raulillo82]

LGTM