"Subscription updated." message is not showing whenever do any update in the subscription from admin panel.

[TechAhead20]

Describe the bug
The "Subscription updated." message is not showing whenever do any update in the subscription from the admin panel.

To Reproduce
Go to any subscription edition page from the backend and update the subscription using the "Update" button. The subscription gets updated but no update message shows when HPOS is enabled.

Expected behavior
The "Subscription updated." message should be showing.

Suggesstion
woocommerce_order_updated_messages filter hook should be using instead of post_updated_messages when HPOS is enabled.

[davefx]

Fixed by #615

[mattallan]

Thanks @TechAhead20 and @davefx