Try not using pipe.

Author: pawchen

.github/workflows/optimize.yml

@@ -20,12 +20,12 @@ jobs:
       - name: Optimize still images
         run: >
           find pages/ \( -iname "*.png" -o -iname "*.jpg" -o -iname "*.jpeg" \)
-          | parallel 'cwebp -q 80 {= $_=Q($_) =} -o {= $_=Q($_); s/\.[^.]+$// =}.webp && rm {= $_=Q($_) =}'
+          -exec parallel 'cwebp -q 80 {} -o {.}.webp && rm {}' ::: {} +
 
       - name: Optimize gif images
         run: >
           find pages/ -iname "*.gif"
-          | parallel 'gif2webp -q 80 {= $_=Q($_) =} -o {= $_=Q($_); s/\.[^.]+$// =}.webp && rm {= $_=Q($_) =}'
+          -exec parallel 'gif2webp -q 80 {} -o {.}.webp && rm {}' ::: {} +
 
       - name: Optimize text
         run: |