Add libopencv and py-opencv needed by opencv package

Add libopencv and py-opencv dependencies. Those packages are required by opencv and build before the opencv package in its recipe.

conda/bob-devel/meta.yaml

@@ -113,6 +113,7 @@ test:
     - pytorch
     - torchvision
     - setuptools
+    - opencv
   commands:
     # we expect these features from ffmpeg:
     - ffmpeg -codecs | grep "DEVI.S zlib"  # [unix]