CI: Purge more during purge step (#33)

#### Problem

CI still fails intermittently by running out of disk space.

#### Summary of changes

Purge more from the runner during the "purge" step.

Author: joncinque

.github/actions/setup/action.yml

@@ -56,6 +56,8 @@ runs:
         sudo rm -rf /usr/local/lib/android
         sudo rm -rf /usr/local/lib/heroku
         sudo rm -rf /imagegeneration
+        sudo rm -rf "$AGENT_TOOLSDIRECTORY"
+        sudo docker image prune --all --force
 
     - name: Install Dependencies
       run: pnpm install --frozen-lockfile