404 and SW fallback pages are included in sitemap.xml

[arrrgi]

Description

gatsby-plugin-sitemap includes dev-404-page, offline-plugin-app-shell-fallback, 404 and 404.html in generated sitemap. See comment on Issue #4562 by @prince0203

Steps to reproduce

Include gatsby-plugin-sitemap in gatsby-config.js with the following GraphQL query:

{
    site {
        siteMetadata {
            siteUrl
        }
    }

    allSitePage {
        edges {
            node {
                path
             }
         }
     }
}

Expected result

404 and offline service worker pages should be excluded from the generated sitemap.xml

Actual result

Dev, 404 and service worker fallback pages were included in the sitemap.xml

Environment

• Gatsby version (npm list gatsby): 1.9.158
• gatsby-cli version (gatsby --version): 1.1.40
• Node.js version: v8.9.1
• Operating System: MacOS

File contents (if changed):

gatsby-config.js:
package.json:
gatsby-node.js:
gatsby-browser.js:
gatsby-ssr.js:

[pieh]

Hey @madcatsu, would you be interested in submitting PR updating defaults? Or maybe even better - adjusting code so it matches for both paths with trailing slash and without one?

[arrrgi]

@pieh I believe this one might be best left to someone with more experience in contributing to Gatsby following the standard process. I'd be happy to just fork and submit a PR with @prince0203 proposed changes if someone else has time to test otherwise.