Java 11

• Switch to Java 11 #87 (@jakzal)
• Update gradle (8.0 -> 8.0.1) ce1a84f (@jakzal)
• Update actions/setup-java to v3 429655e 791678d (@jakzal)
• Update actions/upload-artifact to v3 925dcce (@jakzal)
• Update actions/checkout to v3 0e33706 (@jakzal)
• Bump de.undercouch:gradle-download-task from 5.3.1 to 5.4.0 #86