additional fixes

Author: teverett

.github/workflows/main.yml

@@ -14,12 +14,12 @@ jobs:
       fail-fast: false
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
 
     - name: Set up JDK
-      uses: actions/setup-java@v3
+      uses: actions/setup-java@v4
       with:
-        java-version: 12
-        distribution: 'adopt'
+        java-version: 21
+        distribution: 'temurin'
     - name: Build with Maven
       run: mvn -B package --file pom.xml