Install the test dependencies of the built wheel

When installing the wheel that was built in the `build` job we will
also install the `test` optional dependencies.

Author: mcdonnnj

.github/workflows/build.yml

@@ -295,8 +295,8 @@ jobs:
         run: echo "wheel=$(ls dist/*whl)" >> $GITHUB_OUTPUT
       - name: Update core Python packages
         run: python -m pip install --upgrade pip setuptools wheel
-      - name: Install the built wheel
-        run: python -m pip install ${{ steps.find-wheel.outputs.wheel }}
+      - name: Install the built wheel (along with testing dependencies)
+        run: python -m pip install ${{ steps.find-wheel.outputs.wheel }}[test]
       - name: Run tests
         env:
           RELEASE_TAG: ${{ github.event.release.tag_name }}