Update all tech_writers for stages per FY21 plan

Why is this change being made?

Update all tech_writers for stages per FY21 plan in accordance with https://docs.google.com/spreadsheets/d/1vrCG7N9d9XxKAR46xmu8axLaubZw9ESmzVkLyGotteQ/edit#gid=0

How will this merge request impact page speed?

It wont

Does this MR meet the acceptance criteria?

Yup

Assign to DRI

• Did you assign this change to the correct DRI of the page or information you are changing?

Conformity

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

Related to gitlab-org/gitlab-design#825 (closed)