Feature Request: Sitemap plugin: Allow config to name sitemap file

[jpol0191]

Currently, when using the gatsby-plugin-sitemap you are not able to name the resulting file that contains the sitemap.

I propose that users be allowed to specify the name of the sitemap file in the plugin configs in gatsby-config.js.
Perhaps fileName: "sitemap.xml" for example.

It would also be nice if gatsby gave the option to generate a sitemap it self rather than a sitemap index that points to the sitemap.

[violy]

The default actual default path is /sitemap/sitemap-index.xml where filename sitemap-index.xml is hardcoded. The base path is a plugin option, the name not… why ? Many websites have a /sitemap.xml path convention.

Use a plugin option to configure that string is a good idea.