v3.8.1

Improvements

• feat(api): enable administrators to change demoskill target levels [#709] @themightychris
• feat(tasks): hide removed attachments from student views [#705, SCHOOL-200] @BillClinton

Technical

• docs: update README @themightychris
• fix(e2e): ensure filter menu out of way before opening task [#711] @themightychris