Add Publish Unit Test Results to GH Actions

* Upgrade dependencies
* Fix repos to not use superset to fail for
non-authorized artifacts

* * Revert Dokka plugin - too much JCenter deps
* Add `if: always()` for Test Results in GH Actions

* Add `https://repo.spring.io/release` for docs

* * Use `upload-artifact` action instead -
the `publish-unit-test-result-action` doesn't capture against PRs:
https://github.com/EnricoMi/publish-unit-test-result-action#support-fork-repositories
* `retention-days: 3`

.github/workflows/pr-build-workflow.yml

@@ -44,3 +44,11 @@ jobs:
           NO_REFERENCE_TASK: true
         with:
           arguments: checkAsciidocLinks check
+
+      - name: Capture Test Results
+        if: failure()
+        uses: actions/upload-artifact@v2
+        with:
+          name: test-results
+          path: '*/build/reports/tests/**/*.*'
+          retention-days: 3