Use Java 21 for the build

nakamura-to · nakamura-to · commit 0c1dc981c3a4 · 2024-10-05T11:56:04.000+09:00
diff --git a/.sdkmanrc b/.sdkmanrc
@@ -1,3 +1,3 @@
 # Enable auto-env through the sdkman_auto_env config
 # Add key=value pairs of SDKs to use below
-java=11.0.23-zulu
+java=21-zulu
