Tweak REST API datetime payloads in examples

[wvega]

Summary

Updates the dates in the examples to remove erroneous timezone information.

Story: CH 64817

Details

Also updates a couple of endpoints that were using /api/wc instead of /wp-json/wc.

Before merge

• [x] https://github.com/skyverge/woocommerce-memberships/pull/936 was released in a new version of Memberships