Build: update calibre image configuration

Author: glaubinix

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

@@ -15,6 +15,6 @@ jobs:
         uses: actions/checkout@master
 
       - name: Compress Images
-        uses: calibreapp/image-actions@master
+        uses: calibreapp/image-actions@main
         with:
           githubToken: ${{ secrets.GITHUB_TOKEN }}