CI: fix webcam cache

.github/workflows/selfdrive_tests.yaml

@@ -107,7 +107,7 @@ jobs:
       run: |
         eval "$BUILD"
         docker pull $DOCKER_REGISTRY/$IMAGE_NAME:latest || true
-        docker build --cache-from $DOCKER_REGISTRY/$BASE_IMAGE:latest --cache-from $DOCKER_REGISTRY/$IMAGE_NAME:latest -t $DOCKER_REGISTRY/$IMAGE_NAME:latest -f tools/webcam/Dockerfile .
+        docker build --cache-from $DOCKER_REGISTRY/$IMAGE_NAME:latest -t $DOCKER_REGISTRY/$IMAGE_NAME:latest -f tools/webcam/Dockerfile .
     - name: Build openpilot
       run: docker run --shm-size 1G --rm -v $PWD:/tmp/openpilot -e PYTHONPATH=/tmp/openpilot $DOCKER_REGISTRY/$IMAGE_NAME /bin/sh -c "cd /tmp/openpilot && USE_WEBCAM=1 scons -j$(nproc)"
     - name: Push to container registry