JCR-4827: Update animal-sniffer dependency to 1.21

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/trunk@1903164 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/jackrabbit-parent/pom.xml b/jackrabbit-parent/pom.xml
index c56f9c1..9000f91 100644
--- a/jackrabbit-parent/pom.xml
+++ b/jackrabbit-parent/pom.xml
@@ -185,7 +185,7 @@
       <plugin>
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>animal-sniffer-maven-plugin</artifactId>
-        <version>1.19</version>
+        <version>1.21</version>
         <configuration>
           <signature>
             <groupId>org.codehaus.mojo.signature</groupId>