Upgrade jdk used by release action to 21

Author: EvaristeGalois11

.github/workflows/release.yml

@@ -19,7 +19,7 @@ jobs:
       - name: Set up JDK
         uses: actions/[email protected]
         with:
-          java-version: 17
+          java-version: 21
           distribution: 'zulu'
           cache: 'maven'
           server-id: sonatype-nexus-staging