Update Issue Weight Schedule

Why is this change being made?

In %12.8, we had to quickly weight issues as best we could in order to begin work and it was a team effort. @igor.drozdov was supposed to be doing weights for %12.8 but it ended up being a tag-team effort. Instead, he will do weighting for %12.9 and the other assignments will move back.

/cc @kerrizor since you no longer need to do weights in %12.9!

Does this MR meet the acceptance criteria?

Conformity

• Added description to this MR explaining the reasons for the proposed change, per say-why-not-just-what