Bump checker-qual from 3.21.2 to 3.21.4 (zalando#385)

Bumps [checker-qual](https://github.com/typetools/checker-framework) from 3.21.2 to 3.21.4.
- [Release notes](https://github.com/typetools/checker-framework/releases)
- [Changelog](https://github.com/typetools/checker-framework/blob/master/docs/CHANGELOG.md)
- [Commits](typetools/checker-framework@checker-framework-3.21.2...checker-framework-3.21.4)

---
updated-dependencies:
- dependency-name: org.checkerframework:checker-qual
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

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

pom.xml

@@ -62,7 +62,7 @@
             <dependency>
                 <groupId>org.checkerframework</groupId>
                 <artifactId>checker-qual</artifactId>
-                <version>3.21.2</version>
+                <version>3.21.4</version>
                 <scope>provided</scope>
             </dependency>
             <dependency>