Update checkstyle to latest stable release

Also force it to run with JDK 21

Signed-off-by: Aayush Gupta <aayushgupta219@gmail.com>

Author: theimpulson

extractor/build.gradle.kts

@@ -40,6 +40,13 @@ tasks.test {
     dependsOn(tasks.checkstyleMain) // run checkstyle when testing
 }
 
+// https://checkstyle.org/#JRE_and_JDK
+tasks.withType<Checkstyle>().configureEach {
+    javaLauncher = javaToolchains.launcherFor {
+        languageVersion = JavaLanguageVersion.of(21)
+    }
+}
+
 checkstyle {
     configDirectory = rootProject.file("checkstyle")
     isIgnoreFailures = false

gradle/libs.versions.toml

@@ -4,7 +4,7 @@
 #
 
 [versions]
-checkstyle = "10.26.1"
+checkstyle = "12.3.0"
 gson = "2.13.2"
 jsr305 = "3.0.2"
 junit = "5.14.1"