Merge pull request #5 from bastelfreak/ci

Add Java 21 to CI

Author: bastelfreak

.github/workflows/lein-test.yaml

@@ -13,7 +13,10 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '11', '17' ]
+        java:
+          - '21'
+          - '17'
+          - '11'
     steps:
       - name: Check out repository code
         uses: actions/checkout@v4