update apigen action

Author: splitbrain

.github/workflows/apigen.yml

@@ -13,7 +13,7 @@ jobs:
  steps:
  - uses: actions/checkout@v2
  - name: 📝 ApiGen PHP Document Generator
- uses: varunsridharan/action-apigen@2.0
+ uses: varunsridharan/action-apigen@2.1
  with:
  cached_apigen: 'no'
  env: