Found incompatible version `v1.2.6` for mqttv3 and mqttv5 in the pom.xml for `org.eclipse.paho.sample.mqttclient` project

# Issue Description

When building the `org.eclipse.paho.sample.mqttclient` project, using `mvn clean package` I was getting error stating that dependency jar `v1.2.6` doesn't exist for mqttv3 and mqttv5 as below:

```
[ERROR] Failed to execute goal on project org.eclipse.paho.sample.mqttclient: Could not resolve dependencies for project org.eclipse.paho:org.eclipse.paho.sample.mqttclient:jar:1.2.6
[ERROR] dependency: org.eclipse.paho:org.eclipse.paho.client.mqttv3:jar:1.2.6 (compile)
[ERROR] Could not find artifact org.eclipse.paho:org.eclipse.paho.client.mqttv3:jar:1.2.6 in central (https://repo.maven.apache.org/maven2)
[ERROR] dependency: org.eclipse.paho:org.eclipse.paho.mqttv5.client:jar:1.2.6 (compile)
[ERROR] Could not find artifact org.eclipse.paho:org.eclipse.paho.mqttv5.client:jar:1.2.6 in central (https://repo.maven.apache.org/maven2)
[ERROR]
```

When looking in maven central, for both [mqttv3](https://mvnrepository.com/artifact/org.eclipse.paho/org.eclipse.paho.client.mqttv3) and [mqttv5](https://mvnrepository.com/artifact/org.eclipse.paho/org.eclipse.paho.mqttv5.client) the latest version is `v1.2.5`

Start by opening the pom.xml for the org.eclipse.paho.sample.mqttclient project and reviewing the mqttv3 and mqttv5 client dependency versions. Run mvn clean package to reproduce the resolution failure. Done means both dependencies resolve from Maven Central and the package command completes successfully.

Written by the indexing model from the issue text.