[docs] How to manage suggestions section on the How to Open Pull Requests guide (#18745)
[docs] How to manage suggestions section on the How to Open Pull Requests guide (#18745)

* resolves #14598

Adds a reference guide on how to upgrade Gatsby and its dependencies

* Fixed typos and added related content

* Fixed additional typos

* Fixed additional typos, one with the name of the file, added links for the doc-links.yaml file, escaped < and > characters in markdown thata were causing some errors

* Updated title based on @marcysutton suggestions

Co-Authored-By: Marcy Sutton <63f38fb7a2c9e72439a06d93cefb66621e8fc496@gatsbyjs.com>

* Solves suggested changes such as modifying links for relative urls, removing yarn instructions and alignments to Gatsby style guide

* Apply additional suggestions

Co-Authored-By: Marcy Sutton <63f38fb7a2c9e72439a06d93cefb66621e8fc496@gatsbyjs.com>

* Added a section on how to handle reviews on your PR

* Apply suggestions from code review

Co-Authored-By: Marcy Sutton <63f38fb7a2c9e72439a06d93cefb66621e8fc496@gatsbyjs.com>

gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby