How to use a Gitea secret in a Gitea action for ssh/sftp

Create a secret with the base64 encoded private key as part of the repository settings.

Access the secret in an action like this:

name: Stage blog changes
run-name: ${{ github.actor }} is deploying site to staging 🚀
on: [push]
jobs:
  Explore-Gitea-Actions:
    runs-on: my-ssl-focal
    steps:
      - run: echo "🎉 The job was automatically triggered by a ${{ github.event_name }} event."
      - name: Check out repository code
        uses: actions/checkout@v3
      - run: |
          apt-get update
          apt-get install -y hugo rsync
          hugo --baseURL https://staging.urgarg.dev/          
      - name: Clean the content directory and deploy fresh build 🎉
        env:
           SSH_KEY: ${{ secrets.TEST_BASE64 }}
        run: |
          eval $(ssh-agent)
          echo $SSH_KEY | base64 -d | ssh-add -
          rsync -avz --delete -e "ssh -o StrictHostKeyChecking=no" public/ someuser@urgarg.org:/content/
          ssh-add -D          
      - run: echo "🍏 This job's status is ${{ job.status }}."