Use environment variables in run command

Recommended by https://securitylab.github.com/research/github-actions-untrusted-input/

Author: robtimus

.github/workflows/test.yml

@@ -47,17 +47,21 @@ jobs:
  with:
  fetch-depth: 0
  - name: Rebase PHP8 branch
+ env:
+ USER_EMAIL: ${{ github.event.pusher.email }}
+ USER_NAME: ${{ github.event.pusher.name }}
+ REBASE_TARGET: ${{ github.head_ref || github.ref_name }}
  run: |
- git config user.email "${{ github.event.pusher.email }}"
- git config user.name "${{ github.event.pusher.name }}"
+ git config user.email "$USER_EMAIL"
+ git config user.name "$USER_NAME"
  git pull
  git checkout php8
- git rebase ${{ github.head_ref || github.ref_name }} php8
+ git rebase "$REBASE_TARGET" php8
  git status
  echo 'diff origin/php8:'
  git diff origin/php8
  echo 'diff current:'
- git diff ${{ github.head_ref || github.ref_name }}
+ git diff "$REBASE_TARGET"
  - uses: shivammathur/setup-php@v2
  with:
  php-version: ${{matrix.php}}