adjust gradle build to work with JDK23 that we now pull

Author: ktoso

BuildLogic/src/main/kotlin/build-logic.java-common-conventions.gradle.kts

@@ -17,7 +17,7 @@ plugins {
 
 java {
     toolchain {
-        languageVersion = JavaLanguageVersion.of(22)
+        languageVersion = JavaLanguageVersion.of(23)
     }
 }
 

JavaSwiftKitDemo/build.gradle.kts

@@ -24,7 +24,7 @@ repositories {
 
 java {
     toolchain {
-        languageVersion.set(JavaLanguageVersion.of(22))
+        languageVersion.set(JavaLanguageVersion.of(23))
     }
 }