Migrate docs to spring-asciidoctor-backends

- Use io.spring.asciidoctor.backends:spring-asciidoctor-backends:0.0.5
- Backport #722
- Fixes #723

Author: jvalkeal

spring-shell-docs/pom.xml

@@ -14,8 +14,7 @@
 	<description>Spring Shell reference documentation</description>
 	<properties>
 		<asciidoctor.maven.plugin.version>2.2.2</asciidoctor.maven.plugin.version>
-		<asciidoctorj.pdf.version>1.5.4</asciidoctorj.pdf.version>
-		<asciidoctorj.epub.version>1.5.1</asciidoctorj.epub.version>
+		<spring-asciidoctor-backends.version>0.0.5</spring-asciidoctor-backends.version>
 		<asciidoctorj.version>2.5.1</asciidoctorj.version>
 		<jruby.version>9.2.17.0</jruby.version>
 		<spring-doc-resources.version>0.2.5</spring-doc-resources.version>
@@ -152,83 +151,23 @@
 				<version>${asciidoctor.maven.plugin.version}</version>
 				<dependencies>
 					<dependency>
-						<groupId>org.asciidoctor</groupId>
-						<artifactId>asciidoctorj-pdf</artifactId>
-						<version>${asciidoctorj.pdf.version}</version>
-					</dependency>
-					<dependency>
-						<groupId>org.asciidoctor</groupId>
-						<artifactId>asciidoctorj-epub3</artifactId>
-						<version>${asciidoctorj.epub.version}</version>
+						<groupId>io.spring.asciidoctor.backends</groupId>
+						<artifactId>spring-asciidoctor-backends</artifactId>
+						<version>${spring-asciidoctor-backends.version}</version>
 					</dependency>
 				</dependencies>
 				<executions>
 					<execution>
-						<id>generate-html</id>
-						<phase>generate-resources</phase>
+						<id>generate-html-documentation</id>
+						<phase>prepare-package</phase>
 						<goals>
 							<goal>process-asciidoc</goal>
 						</goals>
 						<configuration>
-							<backend>html5</backend>
-							<attributes>
-								<source-highlighter>highlight.js</source-highlighter>
-								<project-version>${project.version}</project-version>
-								<project-artifactId>${project.artifactId}</project-artifactId>
-								<toc>left</toc>
-								<toc-levels>4</toc-levels>
-								<sectanchors>true</sectanchors>
-								<sectnums />
-								<docinfo>shared</docinfo>
-								<stylesdir>css/</stylesdir>
-								<stylesheet>spring.css</stylesheet>
-								<linkcss>true</linkcss>
-								<icons>font</icons>
-								<highlightjsdir>js/highlight</highlightjsdir>
-								<highlightjs-theme>github</highlightjs-theme>
-							</attributes>
+							<backend>spring-html</backend>
 						</configuration>
 					</execution>
 
-					<execution>
-						<id>generate-pdf</id>
-						<phase>generate-resources</phase>
-						<goals>
-							<goal>process-asciidoc</goal>
-						</goals>
-						<configuration>
-							<outputDirectory>${project.build.directory}/site/reference/pdf</outputDirectory>
-							<backend>pdf</backend>
-							<sourceHighlighter>coderay</sourceHighlighter>
-							<attributes>
-								<project-version>${project.version}</project-version>
-								<project-artifactId>${project.artifactId}</project-artifactId>
-								<icons>font</icons>
-								<pagenums />
-								<sectnums />
-								<toc />
-							</attributes>
-						</configuration>
-					</execution>
-					<execution>
-						<id>generate-epub</id>
-						<phase>generate-resources</phase>
-						<goals>
-							<goal>process-asciidoc</goal>
-						</goals>
-						<configuration>
-							<backend>epub3</backend>
-							<sourceHighlighter>coderay</sourceHighlighter>
-							<attributes>
-								<project-version>${project.version}</project-version>
-								<project-artifactId>${project.artifactId}</project-artifactId>
-								<icons>font</icons>
-								<pagenums />
-								<sectnums />
-								<toc />
-							</attributes>
-						</configuration>
-					</execution>
 				</executions>
 
 				<configuration>
@@ -237,13 +176,16 @@
 					<doctype>book</doctype>
 					<attributes>
 						<version>${project.version}</version>
+						<project-version>${project.version}</project-version>
 						<projectName>${project.name}</projectName>
 						<projectVersion>${project.version}</projectVersion>
 						<snippets>${project.build.directory}/refdocs/snippets/</snippets>
 						<allow-uri-read>true</allow-uri-read>
+						<toc>left</toc>
 						<toclevels>4</toclevels>
 						<numbered>true</numbered>
 						<baseDir>${project.basedir}</baseDir>
+						<starter-artifactId>org.springframework.shell:spring-shell-starter</starter-artifactId>
 					</attributes>
 				</configuration>