tests: run checks downloading images

.github/workflows/run.yml

@@ -0,0 +1,26 @@
+name: Check if download links are working
+
+on:
+  push:
+    branches:
+      - '**'
+
+  pull_request:
+    branches:
+      - '**'
+job:
+  run:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Python 3.12
+      uses: actions/setup-python@v5
+      with:
+        python-version: 3.12
+    - name: Install package
+      run: |
+        python -m pip install --upgrade pip
+        python -m pip install .
+    - name: Run imgsync in download mode only
+      run: glance-imgsync --download-only