Description of problem:
Currently, there is no warning for a user to know that a releasever lock has been set.

This becomes a bigger problem with implementations where the user is not the one setting the releasever.

An example is the LEAPP upgrade from 8 to 9 which in an RHSM scenario, will (attempt [assumes proper entitlement]) to set the releasever to 9.0 on the FirstBoot stage of the upgrade.

Other than reading a note somewhere, a user may not know this has occurred, and maybe be upgrading a non-extended-release system.

It would be useful to have a note printed about a releasever lock during a dnf transaction.

Whether that is from dnf-plugin-subscription-manager or a new plugin that is RHEL specific shipped (since this is RHEL specific), is undecided.

There are a few different ways to implement this, and trigger the message.
We could only trigger when there are no extended-stream entitlements, or we could always trigger as a note during a transaction. If we don't want to expose new stdout msgs, we could also add this info to rhsm.log specifically, though this will be less likely to be brought to a users attention.

Actual results:
I didn't know I had a releasever set.

Expected results:
Tell me always.

Additional info:

Done criteria:

• extend the output of the subscription-manager dnf plugin to show the pinned release, if any
• PR merged to main