Bump vertx-web-client from 3.8.1 to 3.8.4 (#165)

Bumps vertx-web-client from 3.8.1 to 3.8.4.

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

Author: dependabot-preview[bot]

tests/pom.xml

@@ -19,7 +19,7 @@
         <test.app.name>../app/target/apicurio-registry-app-${project.version}-runner</test.app.name>
         <debezium.version>0.10.0.Final</debezium.version>
         <kafka.version>2.3.0</kafka.version>
-        <vertx.version>3.8.1</vertx.version>
+        <vertx.version>3.8.4</vertx.version>
         <scala.version>2.12.10</scala.version>
         <maven.dependency.version>3.1.1</maven.dependency.version>
         <maven.checkstyle.version>3.0.0</maven.checkstyle.version>