[OE-core] Stable release changes now that YP has an LTS program

[akuster808]

Hello,

As Richard has pointed out, The Yocto Project now has a LTS program.  It
means the stable branch life cycles are changing.  The new standard life
span for a stable release will be 7 months before transitioning to
"Community Supported". That extra month is so we can pull in changes
missed in the release.  With Zeus, we are giving it 9 months to help
folks transition  and before it goes to "Community Supported".

The "Community Supported" and "EOL" policies are being work on by the
Yocto TSC.

The LTS and Stable processes are on the YP wiki and where the "Community
Supported" and "EOL" policies/processes will be noted.

https://wiki.yoctoproject.org/wiki/Stable_Release_and_LTS

let me know if anything needs clarification.

regards,
Armin