chore(deps): bump kotlin.version from 1.9.20 to 1.9.21 in /webmvc

Bumps `kotlin.version` from 1.9.20 to 1.9.21.

Updates `org.jetbrains.kotlin:kotlin-maven-allopen` from 1.9.20 to 1.9.21

Updates `org.jetbrains.kotlin:kotlin-maven-plugin` from 1.9.20 to 1.9.21

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlin:kotlin-maven-allopen
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.jetbrains.kotlin:kotlin-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

webmvc/pom.xml

@@ -17,7 +17,7 @@
 
     <properties>
         <java.version>17</java.version>
-        <kotlin.version>1.9.20</kotlin.version>
+        <kotlin.version>1.9.21</kotlin.version>
     </properties>
 
     <dependencies>