The source code of WWW::Pusher is on GitHub. You should have forked the repository and created a pull request to fix the problem.

But I'm not sure you really fixed any issues. You replaced

my $payload  = to_json($args{data}, { allow_nonref => 1 });
[download]

with

my $message = "$args{data}";
my %rec_hash = ('message' => $message);
my $payload = to_json (\%rec_hash, { allow_nonref => 1 });
[download]

(with broken indentation). Which means, your version of the module can only send "message", while the original allows for any data to be sent (not knowing the module's purpose, I'm not sure it's desirable, though). The solution I provided does exactly the same.