GH actions: Ensure uv.lock doesnt contain anything not in pyproject.toml

Author: cyberw

.github/workflows/tests.yml

@@ -50,9 +50,9 @@ jobs:
 
       - run: uv venv
 
-      - name: Install the project
-        run: uv sync
-  
+      - name: Install the project & ensure uv.lock doesnt contain anything not in pyproject.toml
+        run: uv sync && uv lock --check
+
       # any local changes would make hatch-vcs set a "local version" (+dev0...), so we ignore any uv.lock updates:
       - run: git update-index --assume-unchanged uv.lock