GitHub workflows: add kpartx test to build-and-unittest.yaml

Signed-off-by: Martin Wilck <mwilck@suse.com>

Author: mwilck

.github/workflows/build-and-unittest.yaml

@@ -108,3 +108,5 @@ jobs:
         run: rm -f tests/dmevents.out tests/directio.out
       - name: root-test
         run: sudo make DIO_TEST_DEV=/dev/ram0 test
+      - name: kpartx-test
+        run: sudo make -C kpartx test