build distribution unconditionally and perform metadata validation in…

… CI/CD workflow (#1164)

.github/workflows/ci-cd.yml

@@ -72,9 +72,6 @@ jobs:
     needs:
       - test
 
-    # Run only on pushing a tag
-    if: github.event_name == 'push' && contains(github.ref, 'refs/tags/')
-
     steps:
       - uses: actions/checkout@v4
 
@@ -87,6 +84,11 @@ jobs:
           python -m pip install build
           python -m build
 
+      - name: Check release distributions
+        run: |
+          python -m pip install twine
+          python -m twine check --strict dist/*
+
       - name: Upload distributions
         uses: actions/upload-artifact@v4
         with:
@@ -99,6 +101,9 @@ jobs:
     needs:
       - release-build
 
+    # Run only on pushing a tag
+    if: github.event_name == 'push' && contains(github.ref, 'refs/tags/')
+
     permissions:
       # IMPORTANT: this permission is mandatory for trusted publishing
       id-token: write