Fix exec-maven-plugin dependencies

Maven compilation with Java11 fails because there is a misalignment of dependencies. It uses incompatible version of EMF (Eclipse Modeling Framework) core libraries:

0    \[org.eclipse.emf.mwe2.launch.runtime.Mwe2Launcher.main()\] ERROR mf.mwe2.launch.runtime.Mwe2Launcher  - IS_OSGI_RUNNING
[519](https://gitlab.fbk.eu/ESProjects/SDE/-/jobs/1349190#L519)java.lang.NoSuchFieldError: IS_OSGI_RUNNING
[520](https://gitlab.fbk.eu/ESProjects/SDE/-/jobs/1349190#L520)	at org.eclipse.emf.ecore.impl.EPackageRegistryImpl.createGlobalRegistry(EPackageRegistryImpl.java:56)
[521](https://gitlab.fbk.eu/ESProjects/SDE/-/jobs/1349190#L521)	at org.eclipse.emf.ecore.EPackage$Registry.\<clinit\>(EPackage.java:75)
[522](https://gitlab.fbk.eu/ESProjects/SDE/-/jobs/1349190#L522)	at org.eclipse.emf.mwe2.language.Mwe2StandaloneSetupGenerated.createInjectorAndDoEMFRegistration(Mwe2StandaloneSetupGenerated.java:38)
[523](https://gitlab.fbk.eu/ESProjects/SDE/-/jobs/1349190#L523)	at org.eclipse.emf.mwe2.launch.runtime.Mwe2Launcher.run(Mwe2Launcher.java:76)
[524](https://gitlab.fbk.eu/ESProjects/SDE/-/jobs/1349190#L524)	at org.eclipse.emf.mwe2.launch.runtime.Mwe2Launcher.main(Mwe2Launcher.java:37)
[525](https://gitlab.fbk.eu/ESProjects/SDE/-/jobs/1349190#L525)	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[526](https://gitlab.fbk.eu/ESProjects/SDE/-/jobs/1349190#L526)	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
[527](https://gitlab.fbk.eu/ESProjects/SDE/-/jobs/1349190#L527)	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[528](https://gitlab.fbk.eu/ESProjects/SDE/-/jobs/1349190#L528)	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
[529](https://gitlab.fbk.eu/ESProjects/SDE/-/jobs/1349190#L529)	at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:282)
[530](https://gitlab.fbk.eu/ESProjects/SDE/-/jobs/1349190#L530)	at java.base/java.lang.Thread.run(Thread.java:829)

The fix is to specify the correct dependencies in the configuration POM.