Merge pull request #37 from apache/dependabot/maven/ognl-ognl-3.2.21

Bump ognl from 3.2.18 to 3.2.21
diff --git a/pom.xml b/pom.xml
index 69b0a19..bd26125 100644
--- a/pom.xml
+++ b/pom.xml
@@ -213,7 +213,7 @@
     <dependency>
       <groupId>ognl</groupId>
       <artifactId>ognl</artifactId>
-      <version>3.2.18</version>
+      <version>3.2.21</version>
       <scope>test</scope>
     </dependency>
   </dependencies>