Update CI to run against jdk 21 #401

	name: CI

	on:
	push:
	branches: [ main ]
	pull_request:
	branches: [ main ]

	jobs:
	linux:
	name: Linux
	runs-on: ubuntu-latest
	timeout-minutes: 30
	steps:
	- uses: actions/checkout@v2

	- name: Set up JDK 21
	uses: actions/setup-java@v1
	with:
	java-version: '21'

	- name: Cache local Maven repository
	uses: actions/cache@v2
	with:
	path: ~/.m2/repository
	key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
	restore-keys: \|
	${{ runner.os }}-maven-

	- name: Verify
	run: ./mvnw clean verify -U

	- name: Checkstyle
	run: ./mvnw checkstyle:check

	windows:
	name: Windows
	runs-on: windows-latest
	timeout-minutes: 30
	steps:
	- name: Set git to use LF
	run: \|
	git config --global core.autocrlf false
	git config --global core.eol lf

	- uses: actions/checkout@v2

	- name: Set up JDK 21
	uses: actions/setup-java@v1
	with:
	java-version: '21'

	- name: Cache local Maven repository
	uses: actions/cache@v2
	with:
	path: $HOME/.m2/repository
	key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
	restore-keys: \|
	${{ runner.os }}-maven-

	- name: Verify
	run: ./mvnw.cmd clean verify

	- name: Checkstyle
	run: ./mvnw.cmd checkstyle:check

	darwin:
	name: macOS
	runs-on: macos-latest
	timeout-minutes: 30
	steps:
	- uses: actions/checkout@v2

	- name: Set up JDK 21
	uses: actions/setup-java@v1
	with:
	java-version: '21'

	- name: Cache local Maven repository
	uses: actions/cache@v2
	with:
	path: ~/.m2/repository
	key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
	restore-keys: \|
	${{ runner.os }}-maven-

	- name: Verify
	run: ./mvnw clean verify -U

	- name: Checkstyle
	run: ./mvnw checkstyle:check

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