Update deadline for reassessing planning rotation

Why is this change being made?

We originally planned to revisit how we rotate the weighting of issues in Jan CY20. This pushes it out to FY21 to allow for a new EM on the Project Management team.

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