MINOR: ci: add reports for test fails

Author: oktalz

.gitlab/unit-tests.yml

@@ -1,5 +1,7 @@
 unit-tests:
   needs: ["diff", "tidy"]
+  variables:
+    GOTESTSUM_JUNITFILE: "unit-tests-report.xml"
   rules:
     - if: $CI_PIPELINE_SOURCE == 'merge_request_event'
     - if: "$CI_PROJECT_NAMESPACE != 'haproxy-controller/community' && $CI_PIPELINE_SOURCE == 'push'"
@@ -13,3 +15,9 @@ unit-tests:
     - export PATH=$PATH:/root/go/bin
   script:
     - task test
+  artifacts:
+    when: always
+    paths:
+      - unit-tests-report.xml
+    reports:
+      junit: unit-tests-report.xml