Update Antora configuration and dependencies

build.gradle

@@ -4,19 +4,5 @@ plugins {
 }
 
 antora {
-	version = '3.2.0-alpha.2'
 	options = [clean: true, fetch: true, stacktrace: true]
-	environment = [
-		'ALGOLIA_API_KEY': '9d489079e5ec46dbb238909fee5c9c29',
-		'ALGOLIA_APP_ID': 'WB1FQYI187',
-		'ALGOLIA_INDEX_NAME': 'springdocs',
-	]
-	// NOTE remember to update the versions in lib/antora/templates/per-branch-antora-playbook.yml as well
-	dependencies = [
-		'@antora/atlas-extension': '1.0.0-alpha.1',
-		'@antora/collector-extension': '1.0.0-alpha.3',
-		'@asciidoctor/tabs': '1.0.0-beta.3',
-		'@springio/antora-extensions': '1.7.0',
-		'@springio/asciidoctor-extensions': '1.0.0-alpha.8',
-	]
 }