Add Candlepin and Pulpcore version update step to branching procedures

[ogajduse]

Problem

After branching Foreman (e.g., for 3.16), we may need to update Candlepin and Pulpcore versions in the nightly/develop branch, but this step is not currently documented in our branching procedures.

Context

For Foreman 3.16 branching, we needed to create these PRs:

• Update Katello repos to Pulpcore 3.73: Update Katello repos to Pulpcore 3.73 foreman-packaging#12372
• Update Katello-repos with Candlepin 4.6: Update Katello-repos with Candlepin 4.6 foreman-packaging#12373

While these updates are not required for every release, when new versions of Candlepin or Pulpcore are available and should be included in the next release cycle, we need to ensure this step is not forgotten.

Proposal

We should add a step to the Foreman branching procedure (procedures/foreman/branch.md.erb) that instructs the Release Owner and/or Release Engineer to:

1. Check if new Candlepin and Pulpcore versions are available and should be updated
2. Update the versions in packages/katello/katello-repos/katello-repos.spec if needed
3. Create PRs for these updates when necessary

Question

Where should this step be placed in the branching procedure?

Some options:

• During "Preparing build systems" phase with other packaging updates
• After branching but before bumping develop versions
• As part of the Release Engineer tasks
• As a Release Owner responsibility

Looking for feedback on the best placement for this step to ensure it doesn't get missed when updates are needed in future releases.

[ogajduse]

This looks like a duplicate of #471

[ogajduse]

#374 might be slightly related to this one.