Bump animal-sniffer-maven-plugin from 1.16 to 1.21

Bumps [animal-sniffer-maven-plugin](https://github.com/mojohaus/animal-sniffer) from 1.16 to 1.21.
- [Release notes](https://github.com/mojohaus/animal-sniffer/releases)
- [Commits](https://github.com/mojohaus/animal-sniffer/compare/animal-sniffer-parent-1.16...animal-sniffer-parent-1.21)

---
updated-dependencies:
- dependency-name: org.codehaus.mojo:animal-sniffer-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/pom.xml b/pom.xml
index 2c6086b..2457038 100644
--- a/pom.xml
+++ b/pom.xml
@@ -329,7 +329,7 @@
       <plugin>
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>animal-sniffer-maven-plugin</artifactId>
-        <version>1.16</version>
+        <version>1.21</version>
         <configuration>
           <signature>
             <groupId>org.codehaus.mojo.signature</groupId>