delete all github workflow action runs.. Can require multiple runs if you have thousands of actions.

clean_actions.sh

#!/bin/bash
OWNER=org
REPO=therepo
#GET DAT SHIZ
WORKFLOW_ID=$(gh workflow list|rev|cut -f 1|rev)

#DELETE DAT SHIZ
for i in ${WORKFLOW_ID[@]}; do
    gh api -X GET /repos/$OWNER/$REPO/actions/workflows/$i/runs | jq '.workflow_runs[] | .id'
    gh api -X GET /repos/$OWNER/$REPO/actions/workflows/$i/runs | jq '.workflow_runs[] | .id' | xargs -I{} gh api -X DELETE /repos/$OWNER/$REPO/actions/runs/{}
done