Upgrade to Thymeleaf Layout Dialect 2.2.1

Closes gh-8992

spring-boot-dependencies/pom.xml

@@ -182,7 +182,7 @@
 		<thymeleaf.version>3.0.5.RELEASE</thymeleaf.version>
 		<thymeleaf-spring5.version>3.0.5.M3</thymeleaf-spring5.version>
 		<thymeleaf-extras-springsecurity4.version>3.0.2.RELEASE</thymeleaf-extras-springsecurity4.version>
-		<thymeleaf-layout-dialect.version>2.1.2</thymeleaf-layout-dialect.version>
+		<thymeleaf-layout-dialect.version>2.2.1</thymeleaf-layout-dialect.version>
 		<thymeleaf-extras-data-attribute.version>2.0.1</thymeleaf-extras-data-attribute.version>
 		<thymeleaf-extras-java8time.version>3.0.0.RELEASE</thymeleaf-extras-java8time.version>
 		<tomcat.version>8.5.14</tomcat.version>