dependabot for release branches

[SergeyKanzhelev]

What would you like to be added:

Release branches for all supported version and add dependabot configuration for currently supported branches.

Why is this needed:

As security becoming a higher priority with AI expansion, keeping the up to date release branches is more important then before. Even though downstream support their own branches, keeping those upstream will make it easier for dependant OSS projects to consume safer binaries.

[saschagrunert]

Yeah, in the past we tried to avoid release branches at all because of the higher maintenance effort. This also means that we fix CVE's only when the project parts are actually exploitable by code.

[SergeyKanzhelev]

code scanners really do not like it that much, but the attack surface in these binaries is minimal for sure.

Let's see if there will be more asks for it. If not, I am ok with suggesting that it is downstream problem