deps: update dependency commons-io:commons-io to v2.21.0 (#4198)

Co-authored-by: rahul2393 <irahul@google.com>

Author: renovate-bot

google-cloud-spanner-executor/pom.xml

@@ -189,7 +189,7 @@
     <dependency>
       <groupId>commons-io</groupId>
       <artifactId>commons-io</artifactId>
-      <version>2.20.0</version>
+      <version>2.21.0</version>
     </dependency>
 
     <!-- Test dependencies -->