Adjust version rhn web.conf

[raulillo82]

What does this PR change?

Adjust the version number in web/conf/rhn_web.conf (web.version.uyuni)

GUI diff

Before: Version will be shown as 2023.04 in the web-UI
After: Version will be shown as 2023.09 in the web-UI

• DONE

Documentation

• No documentation needed: Simply a version bump. The version will be stated in the release notes.

• DONE

Test coverage

• No tests: already covered

• DONE

Links

Tracks (part of) https://github.com/SUSE/spacewalk/issues/21280

• 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