Update vertx version to 4.5.21 (#344)

Author: cYKatherine

pom.xml

@@ -16,7 +16,7 @@
         <maven-surefire-plugin.version>2.22.2</maven-surefire-plugin.version>
         <exec-maven-plugin.version>3.0.0</exec-maven-plugin.version>
 
-        <vertx.version>4.5.18</vertx.version>
+        <vertx.version>4.5.21</vertx.version>
         <vertx-maven-plugin.version>1.0.22</vertx-maven-plugin.version>
         <micrometer.version>1.12.2</micrometer.version>
         <junit-jupiter.version>5.10.3</junit-jupiter.version>