fix: deps/npm/docs/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-QS-14724253

Author: snyk-bot

deps/npm/docs/package.json

@@ -20,7 +20,7 @@
     "gatsby-plugin-prefetch-google-fonts": "^1.4.3",
     "gatsby-plugin-react-helmet": "^3.1.4",
     "gatsby-plugin-root-import": "^2.0.5",
-    "gatsby-plugin-sharp": "^2.2.13",
+    "gatsby-plugin-sharp": "^2.13.0",
     "gatsby-plugin-styled-components": "^3.1.11",
     "gatsby-remark-autolink-headers": "^2.1.10",
     "gatsby-remark-prismjs": "^3.3.13",