Adds .qgz files on --help description

Lists .qgz files in the possible project files to open from the command line

Author: SrNetoChan

src/app/main.cpp

@@ -152,7 +152,7 @@ void usage( const QString &appName )
       << QStringLiteral( "\t[--]\t\ttreat all following arguments as FILEs\n\n" )
       << QStringLiteral( "  FILE:\n" )
       << QStringLiteral( "    Files specified on the command line can include rasters,\n" )
-      << QStringLiteral( "    vectors, and QGIS project files (.qgs): \n" )
+      << QStringLiteral( "    vectors, and QGIS project files (.qgs and .qgz): \n" )
       << QStringLiteral( "     1. Rasters - supported formats include GeoTiff, DEM \n" )
       << QStringLiteral( "        and others supported by GDAL\n" )
       << QStringLiteral( "     2. Vectors - supported formats include ESRI Shapefiles\n" )