ci: add github job to validate client_schemas on push and PRs

.github/workflows/test.yaml

@@ -43,6 +43,25 @@ jobs:
         run: |
           make build-test
 
+  validate:
+    name: Validate
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python:
+          - "3.10"
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v3
+      - name: Setup Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python }}
+      - name: Install dependencies
+        run: pip install tox
+      - name: Run validation tests
+        run: tox -e validate
+
   unit-tests:
     needs: lint
     name: Unit tests