chore(deps): update dependency io.vertx:vertx-core to v3.9.1 (#2914)
chore(deps): update dependency io.vertx:vertx-core to v3.9.1 (#2914)


GoogleCloudPlatform/java-docs-samples,GoogleCloudPlatform/java-docs-samples,GoogleCloudPlatform/java-docs-samples,GoogleCloudPlatform/java-docs-samples,GoogleCloudPlatform/java-docs-samples,GoogleCloudPlatform/java-docs-samples