Add check-package step also to 'test' workflow

This ensures we do not have any surprises when we try to deploy,
which uses the same step to generate the package.

.github/workflows/test.yml

@@ -10,6 +10,14 @@ on:
       - "*"
 
 jobs:
+
+  check-package:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - name: Build and Check Package
+      uses: hynek/build-and-inspect-python-package@v1.5
+
   test:
 
     runs-on: ${{ matrix.os }}