Update classroom.yml

Author: kappsegla

.github/workflows/classroom.yml

@@ -20,7 +20,7 @@ jobs:
       - uses: actions/setup-java@v5
         with:
           distribution: 'temurin'
-          java-version: '24'
+          java-version: '25'
       - uses: actions/checkout@v5
       - name: Run autograder
         id: grading