Run tests with Java 21

Time to move on. Source still targets Java 11, but this allows Gradle upgrades which require 17+.

Signed-off-by: Chad Wilson <[email protected]>

Author: chadlwilson

.github/workflows/tests.yml

@@ -62,7 +62,7 @@ jobs:
         uses: actions/setup-java@v4
         with:
           distribution: 'temurin'
-          java-version: '11'
+          java-version: '21'
 
       - uses: getgauge/setup-gauge@master
         with: