Bump animal.sniffer.version from 1.20 to 1.21 (#496)

Bumps `animal.sniffer.version` from 1.20 to 1.21.

Updates `animal-sniffer-annotations` from 1.20 to 1.21
- [Release notes](https://github.com/mojohaus/animal-sniffer/releases)
- [Commits](mojohaus/animal-sniffer@animal-sniffer-parent-1.20...animal-sniffer-parent-1.21)

Updates `animal-sniffer-maven-plugin` from 1.20 to 1.21
- [Release notes](https://github.com/mojohaus/animal-sniffer/releases)
- [Commits](mojohaus/animal-sniffer@animal-sniffer-parent-1.20...animal-sniffer-parent-1.21)

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

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

pom.xml

@@ -106,7 +106,7 @@
 
     <mockito.version>4.3.1</mockito.version>
     <access-modifier-checker.version>1.27</access-modifier-checker.version>
-    <animal.sniffer.version>1.20</animal.sniffer.version>
+    <animal.sniffer.version>1.21</animal.sniffer.version>
 
     <!-- To opt in to @Restricted(Beta.class) APIs, set to true: -->
     <useBeta>false</useBeta>