I have released an update for the WP-Members Memberships for WooCommerce extension. This update includes renewal reminders.
Note that for the email renewal reminders to work, you MUST be using WP-Members 3.3. If you are on a version less than that, the user expiration dates are not properly formatted.
Also note that the email for the renewal reminder is a WooCommerce email, not a WP-Members email. This is to provide consistency with the other emails within WooCommerce. Like other WC emails, the template (which is included and used by default in the plugin) can be copied to your theme folder and customized. Also, the email is managed within the WC settings, not WP-Members.
I have updated the documentation to include information on setup: