include version 21 in tests (#78)

Author: aarsilv

.github/workflows/lint-test-sdk.yml

@@ -30,7 +30,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java-version: ['8', '11', '17'] # Define the Java versions to test against
+        java-version: ['8', '11', '17', '21'] # Define the Java versions to test against
     steps:
       - name: Display Testing Details
         run: |