Fluent Package v5 LTS will reach end of support at
the end of 2025.
Fluent Package v6 LTS will be supported until at least
the end of 2027.
This change updates the apt repository configuration and package version
to use Fluent Package v6 LTS for Ubuntu, Debian and RHEL.
No changes to existing Fluentd configuration files are required.
Change-Id: Iaf3c4de859986629f9768563a319fe0385acff6a
Signed-off-by: Piotr Milewski <vurmil@gmail.com>