Workflow updates for Java 21, etc.

Author: mikebroberts

.github/workflows/integration-test.yml

@@ -23,18 +23,17 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
 
-      - name: Set up Java 8
+      - name: Set up Java 21
         uses: actions/setup-java@v4
         with:
           distribution: 'corretto'
-          java-version: '8'
+          java-version: '21'
           cache: 'maven'
 
       - name: Set up SAM CLI
         uses: aws-actions/setup-sam@v2
         with:
           use-installer: true
-          version: '1.53.0'  # Version from ~2022, compatible with 2020 templates
 
       - name: Configure AWS credentials
         uses: aws-actions/configure-aws-credentials@v4