fix workflow

Author: tillsteinbach

.github/workflows/build.yml

@@ -32,6 +32,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+        if [ -f image_extra_requirements.txt ]; then pip install -r image_extra_requirements.txt; fi
         if [ -f setup_requirements.txt ]; then pip install -r setup_requirements.txt; fi
         if [ -f test_requirements.txt ]; then pip install -r test_requirements.txt; fi
     - name: Lint