build(deps): bump gatsby-plugin-sitemap from 4.4.0 to 4.6.0 in /docs (#2148)

Author: dependabot[bot]

docs/package-lock.json

@@ -25,7 +25,7 @@
     "gatsby-plugin-react-svg": "^3.0.1",
     "gatsby-plugin-robots-txt": "^1.6.8",
     "gatsby-plugin-sharp": "^3.8.0",
-    "gatsby-plugin-sitemap": "^4.4.0",
+    "gatsby-plugin-sitemap": "^4.6.0",
     "gatsby-remark-autolink-headers": "^2.11.0",
     "gatsby-remark-copy-linked-files": "^4.5.0",
     "gatsby-remark-embedder": "^4.2.0",