CI: Generate and archive kover report

.github/workflows/tests.yml

@@ -23,6 +23,17 @@ jobs:
       - uses: actions/checkout@v3
       - name: Run tests
         run: ./gradlew test $CI_GRADLE_ARG_PROPERTIES
+      - name: Generate kover report
+        if: always()
+        run: ./gradlew koverMergedReport $CI_GRADLE_ARG_PROPERTIES
+
+      - name: Archive kover report
+        if: always()
+        uses: actions/upload-artifact@v3
+        with:
+          name: kover-results
+          path: |
+            **/build/reports/kover/merged
 
       - name: Archive test results on error
         if: failure()