Add <licenses> block to pom.xml

Please add the Apache 2.0 License block with the correct SPDX ID in pom.xml so that the licenses tools reports the correct license.

```
<licenses>
  <license>
    <name>Apache-2.0</name>
    <url>https://www.apache.org/licenses/LICENSE-2.0.txt</url>
    <distribution>repo</distribution>
    <comments>A business-friendly OSS license</comments>
  </license>
</licenses>
```

/Ove