Fix grammar in CatalogStaging.md

[brendanWeb]

Fixes a grammatical error that could confuse readers.

[tanberry]

Hi @brendanWeb thanks for your PR. The original sentence is referring to the the list of modules that have dependencies upon the Magento_CatalogStaging module... not the modules upon which the Magento_CatalogStaging module itself depends.

The require section of the composer.json file lists those modules that depend on Magento_CatalogStaging, or "require" the Magento_CatalogStaging module.

Please let us know if this makes sense; it is quite possible that we still have it worded in a confusing way. Thanks again!

[tanberry]

We are closing the PR, but please do let us know if the wording is still confusing. Thanks!