Fix for maven warning, pom.version --> project.version

Fix for the following Maven warning:

```bash
$ mvn install
[INFO] Scanning for projects...
...
[WARNING] 
[WARNING] Some problems were encountered while building the effective model for org.isatools:ISAcreator:bundle:1.7.7
[WARNING] The expression ${pom.version} is deprecated. Please use ${project.version} instead.
[WARNING] 
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING] 
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[WARNING]
```