Hi there,
this file is a WooCommerce template, if the file is missing, the original template from WooCommerce is called and used. This is how the WooCommerce template hierarchy works: https://woocommerce.com/document/template-structure/
In particular the file was removed from this version because no longer needed as it don’t need modifications from the original one from WooCommerce itself. So the update is safe for everyone, even users with customized version included in the child theme.
Maybe you have a code customization in your child theme or in some plugin which was including directly that file in that specific path?
Note that if you add the file in that directory, you will miss it again in the next update. The right thing to do is, in case you need customizations on that file to move it inside /wp-content/themes/yith-proteo-child/woocommerce/content-product.php.
This way you will not loose it on every update. But, like I first said, you have to check if you are somehow manually including this file in a custom code referring to that specific path from the parent theme.
