Bump jcabi-log from 0.20.0 to 0.21.0

Bumps [jcabi-log](https://github.com/jcabi/jcabi-log) from 0.20.0 to 0.21.0.
- [Release notes](https://github.com/jcabi/jcabi-log/releases)
- [Commits](https://github.com/jcabi/jcabi-log/commits/0.21.0)

---
updated-dependencies:
- dependency-name: com.jcabi:jcabi-log
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

pom.xml

@@ -73,7 +73,7 @@ OF THE POSSIBILITY OF SUCH DAMAGE.
     <dependency>
       <groupId>com.jcabi</groupId>
       <artifactId>jcabi-log</artifactId>
-      <version>0.20.0</version>
+      <version>0.21.0</version>
     </dependency>
     <dependency>
       <groupId>com.jcabi</groupId>