Update gaz.md

Update the GAZ project to active.
Make the gaz_countries.owl file the default file for the project.

Author: lschriml

ontology/gaz.md

@@ -23,5 +23,5 @@ products:
 - id: gaz.obo
 repository: https://github.com/EnvironmentOntology/gaz
 tracker: https://github.com/EnvironmentOntology/gaz/issues
-activity_status: inactive
+activity_status: active
 ---