Add tag for discoverability

`image-classification` is how the task is called on the Hub, so this will help with discoverability. Very cool work btw!! I really like the space

README.md

@@ -4,6 +4,7 @@ tags:
   - resnet
   - computer-vision
   - classification
+  - image-classification
   - binary-classification
 license:
   - cc0-1.0