Upload test results in the end of every build

this allows downloading test report from GitHub actions in case of test failure.

.github/workflows/build.yml

@@ -52,3 +52,12 @@ jobs:
       - name: 'Test with downstream project'
         if: ${{ matrix.java-version == env.jdk_for_downstream && matrix.runs-on == env.os_for_downstream}}
         run: cd datafaker_gen && ./mvnw clean install -Ddatafaker.version=${{ steps.version-extract.outputs.release_version }} -DskipBigQueryIntegrationTests=true
+      - name: 'Upload test results'
+        uses: actions/upload-artifact@v4
+        if: always()
+        with:
+          name: test-report-${{matrix.runs-on}}-${{matrix.java-version}}
+          retention-days: 14
+          path: |
+            **/target/site
+            **/target/surefire-reports