Compile with java 21 instead of 20 (#2320)

* Compile with java 21 instead of 20

Closes #2319

.github/actions/setup-gradle-build/action.yml

@@ -22,7 +22,7 @@ runs:
         distribution: 'zulu'
         java-version: | # last version (set as default) should match all `jvmToolchain(xxx)` calls in the project
           ${{ inputs.additional-java-versions }}
-          20
+          21
 
       # Please note these settings will override the ones set via `gradle.properties` committed to the repository - https://docs.gradle.org/current/userguide/build_environment.html#sec:gradle_configuration_properties
       # List of optimizations:

.github/workflows/generate-changelog.yml

@@ -14,7 +14,7 @@ jobs:
       - uses: actions/setup-java@v3
         with:
           distribution: 'zulu'
-          java-version: 19
+          java-version: 21
 
       - uses: gradle/gradle-build-action@v2
         with:

CHANGELOG.md

@@ -14,6 +14,8 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 
 ### Changed
 
+* Use Java 21 for compilation [#2319](https://github.com/pinterest/ktlint/issues/2319)
+
 ## [1.0.1] - 2023-10-13
 
 ### 🆕 Features

gradle/libs.versions.toml

@@ -1,6 +1,6 @@
 [versions]
 # The java-compilation version is the latest supported (not necessarily LTS) version of Java. It should be identical to Java-version used in `actions/setup-java`
-java-compilation = "20"
+java-compilation = "21"
 # The java-target version is the lowest supported LTS version of Java. Jar's produced are bytecode compatible with this version.
 java-target = "8"
 kotlin = "1.9.10"