Add jsonschema dependency to fix GitHub Actions workflow

.github/workflows/tests.yaml

@@ -23,7 +23,7 @@ jobs:
       - name: Install dependencies
         run: |
           pip install --upgrade pip
-          pip install .[all]
+          pip install .[all] jsonschema
 
       - name: Install dcm2niix posix
         if: runner.os != 'Windows'