Add test to validate schema

Author: manisandro

.github/workflows/main.yml

@@ -3,6 +3,22 @@ name: build
 on: [push]
 
 jobs:
+    test:
+      runs-on: ubuntu-latest
+      steps:
+
+      - uses: actions/checkout@master
+
+      - name: Setting up python 3.12
+        uses: actions/setup-python@v5
+        with:
+            python-version: '3.12'
+
+      - name: Validate schema
+        run: |
+          python -m pip install check-jsonschema
+          check-jsonschema --check-metaschema schemas/qwc-map-viewer.json
+
     build:
       runs-on: ubuntu-latest
       if: github.event_name == 'push' && contains(github.ref, 'refs/tags/')