updated readme with further build instructions #96

	# This workflow will build a Java project with Maven
	# For more information see:
	# - https://help.github.com/actions/language-and-framework-guides/building-and-testing-java-with-maven
	# - https://github.com/actions/setup-java
	# - https://github.com/actions/starter-workflows/edit/master/ci/maven.yml
	# - https://github.com/actions/cache/blob/master/examples.md#java---maven

	name: Maven test, build and verify

	on:
	push:
	branches-ignore:
	- main
	pull_request:
	branches-ignore:
	- main

	jobs:
	build:
	runs-on: ubuntu-latest
	strategy:
	matrix:
	# test against latest update of each major Java version:
	java: [ 8, 11, 17, 20 ]
	name: Build with Java ${{ matrix.java }}

	steps:
	- uses: actions/checkout@v2
	with:
	lfs: true
	- name: Checkout LFS objects
	run: git lfs checkout

	- name: Set up JDK ${{ matrix.java }}
	uses: actions/setup-java@v1
	with:
	java-version: ${{ matrix.java }}

	- name: Cache Maven dependencies between builds
	uses: actions/cache@v1
	with:
	path: ~/.m2/repository
	key: ${{ runner.os }}-maven-jdk${{ matrix.java }}-${{ hashFiles('**/pom.xml') }}
	restore-keys: \|
	${{ runner.os }}-maven-jdk${{ matrix.java }}-

	- name: Build and Verify with Maven on Java ${{ matrix.java }}
	run: mvn -B --show-version -Dmaven.skip.macSigning=true clean verify

	- name: Archive App & Jar build snapshots for Java 8
	uses: actions/upload-artifact@v2
	if: matrix.java == '8'
	with:
	name: App-Snapshots-Java-${{ matrix.java }}
	path: target/EPUB-Checker-*.zip

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