Add -q bash -c

Author: pawchen

.github/workflows/publish_book.yml

@@ -37,7 +37,7 @@ jobs:
       - name: Optimize still images
         run: |
           find pages/ \( -iname "*.png" -o -iname "*.jpg" -o -iname "*.jpeg" \) -print0 | \
-          parallel -0 '
+          parallel -0 -q bash -c '
             file="{}"
             output="{.}.webp"
 
@@ -56,7 +56,7 @@ jobs:
       - name: Optimize gif images
         run: |
           find pages/ -iname "*.gif" -print0 | \
-          parallel -0 '
+          parallel -0 -q bash -c '
             file="{}"
             output="{.}.webp"