Bump javancss-maven-plugin from 2.0 to 2.1

Bumps javancss-maven-plugin from 2.0 to 2.1.

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/pom.xml b/pom.xml
index 2eec638..8df9b63 100644
--- a/pom.xml
+++ b/pom.xml
@@ -433,7 +433,7 @@
           <plugin>
             <groupId>org.codehaus.mojo</groupId>
             <artifactId>javancss-maven-plugin</artifactId>
-            <version>2.0</version>
+            <version>2.1</version>
           </plugin>
           <plugin>
             <groupId>org.codehaus.sonar-plugins</groupId>