ci: fix test reports path

Author: Genyus

.github/workflows/classroom-autograding.yml

@@ -31,7 +31,7 @@ jobs:
         uses: dorny/test-reporter@v2
         with:
           name: JUnit Results
-          path: target/surefire-reports/**/*.xml
+          path: **/target/surefire-reports/**/*.xml
           reporter: java-junit
 
       - name: Report score back to Classroom