cmake --workflow: Convert implementation to internal role

Previously it initialized as `PROJECT` but didn't actually add any
commands.  This was likely copied from the `--build` implementation,
which has since been converted to `INTERNAL` too.

Source/cmakemain.cxx

@@ -1065,7 +1065,7 @@ int do_workflow(int ac, char const* const* av)
     return 1;
   }
 
-  cmake cm(cmake::CommandSet::None, cmState::Role::Project);
+  cmake cm(cmake::CommandSet::None, cmState::Role::Internal);
   cmSystemTools::SetMessageCallback(
     [&cm](std::string const& msg, cmMessageMetadata const& md) {
       cmakemainMessageCallback(msg, md, &cm);