Add a similar TODO comment for Vert.x

Author: ShreckYe

buildSrc/src/main/kotlin/VersionsAndDependencies.kt

@@ -5,6 +5,7 @@ import com.huanshankeji.CommonVersions
 val projectVersion = "0.7.0-SNAPSHOT"
 
 // TODO remove Exposed's explicit version when migration to Exposed 1.0.0 is complete
+// TODO remove Vert.x's explicit version when migration to Vert.x 5 is complete
 // TODO Kotest 6 requires Java 11
 val commonVersions = CommonVersions(exposed = "0.61.0", vertx = "4.5.21", kotest = "5.9.1")
 val commonDependencies = CommonDependencies(commonVersions)