Adding "property" attribute for scripts parameter in execute mojo

[mawasak]

Without "property" attribute in "Parameter" calling execute mojo from command line is not working.
For example for call:
mvn org.codehaus.gmavenplus:gmavenplus-plugin:4.0.2-SNAPSHOT:execute -Dscripts="src\main\groovy\FooScript.groovy"

I got:
The parameters 'scripts' for goal org.codehaus.gmavenplus:gmavenplus-plugin:4.0.2-SNAPSHOT:execute are missing or invalid

When "property" attribute is added, execute mojo is working, eg.:

mvn org.codehaus.gmavenplus:gmavenplus-plugin:4.0.2-SNAPSHOT:execute -Dgp.exec.scripts="src\main\groovy\FooScript.groovy"

[keeganwitt]

Thanks for the PR! I changed the variable name since other properties didn't include a prefix. I'm not sure if that was the best choice to have made (I think that dates back to the original GMaven days), but thought it was better to be consistent. I also added a couple additional properties I thought might be useful.

[mawasak]

Thanks.
Regarding properties names I added prefix in case of any possible conflict in other plugins. I think the same reason was in case of exec-maven-plugin for java, eg.:
https://github.com/mojohaus/exec-maven-plugin/blob/master/src/main/java/org/codehaus/mojo/exec/ExecJavaMojo.java#L76

But yes - shorter version is nice to use and consistent with parameter name.

[keeganwitt]

I had the same thought about collisions, but wasn't seeing prefixes in official Maven plugins. It appears they don't make any specific recommendations about that.

What I meant by consistency was with the other parameter properties that already exist. I'd like them to be all prefixed, or none of them.