Merge pull request #52 from javascripteverywhere/dependabot/npm_and_yarn/gatsby-plugin-sitemap-2.2.20

Bump gatsby-plugin-sitemap from 2.0.11 to 2.2.20

Author: ascott1

package-lock.json

@@ -15,7 +15,7 @@
     "gatsby-plugin-offline": "^2.0.25",
     "gatsby-plugin-react-helmet": "^3.0.11",
     "gatsby-plugin-sharp": "^2.0.32",
-    "gatsby-plugin-sitemap": "^2.0.11",
+    "gatsby-plugin-sitemap": "^2.2.20",
     "gatsby-plugin-styled-components": "^3.1.11",
     "gatsby-source-filesystem": "^2.1.33",
     "gatsby-transformer-sharp": "^2.1.17",