Add zbar dep to CI

.builds/alpine.yml

@@ -4,6 +4,7 @@ packages:
   - samurai
   - gtk+3.0-dev
   - tiff-dev
+  - zbar-dev
 tasks:
   - build: |
       cd megapixels

.builds/arch.yml

@@ -3,6 +3,7 @@ packages:
   - meson
   - ninja
   - gtk3
+  - zbar
 tasks:
   - build: |
       cd megapixels