Remove the calibreapp action

.github/workflows/calibreapp-image-actions.yml

@@ -1,12 +0,0 @@
-name: Compress images
-on: pull_request
-jobs:
-  build:
-    name: calibreapp/image-actions
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@master
-      - name: calibreapp/image-actions
-        uses: docker://calibreapp/github-image-actions
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}