upgrade Gradle Antora plugin and extension packages

build.gradle

@@ -1,11 +1,11 @@
 plugins {
 	id 'base'
-	id 'org.antora' version '1.0.0-alpha.3'
+	id 'org.antora' version '1.0.0-alpha.5'
 }
 
 antora {
 	version = '3.2.0-alpha.2'
-	options = ['--clean', '--fetch', '--stacktrace']
+	options = [clean: true, fetch: true, stacktrace: true]
 	environment = [
 		'ALGOLIA_API_KEY': '82c7ead946afbac3cf98c32446154691',
 		'ALGOLIA_APP_ID': '244V8V9FGG',
@@ -13,10 +13,10 @@ antora {
 	]
 	dependencies = [
 		'@antora/atlas-extension': '1.0.0-alpha.1',
-		'@antora/collector-extension': '1.0.0-alpha.2',
+		'@antora/collector-extension': '1.0.0-alpha.3',
 		'@asciidoctor/tabs': '1.0.0-alpha.11',
 		'@opendevise/antora-release-line-extension': '1.0.0-alpha.2',
 		'@springio/antora-extensions': '1.0.0-alpha.2',
-		'@springio/asciidoctor-extensions': '1.0.0-alpha.7',
+		'@springio/asciidoctor-extensions': '1.0.0-alpha.8',
 	]
 }