Updated semaphore.yml to use Java 21

Author: DenBond7

.semaphore/semaphore.yml

@@ -40,7 +40,7 @@ global_job_config:
       - ping fel.localhost -c 1
       - ping fel.flowcrypt.test -c 1
       # use JAVA 17 by default
-      - sem-version java 17
+      - sem-version java 21
       # general settings
       - export PATH=${ANDROID_HOME}/emulator:${ANDROID_HOME}/cmdline-tools/latest/bin:${ANDROID_HOME}/platform-tools:${PATH}
       - sudo rm -rf ~/.rbenv ~/.phpbrew