Set up JDK 8 too for the JVM toolchain version in the "check" job

Author: ShreckYe

.github/workflows/ci.yml

@@ -18,6 +18,11 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
+    - name: Set up JDK 8
+      uses: actions/setup-java@v4
+      with:
+        java-version: '8'
+        distribution: 'temurin'
     - name: Set up JDK 17
       uses: actions/setup-java@v4
       with: