fix: docs/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-INFLIGHT-6095116

docs/package.json

@@ -5,14 +5,14 @@
   "dependencies": {
     "@commonground/design-system": "12.5.0",
     "formik": "2.1.4",
-    "gatsby": "2.24.86",
+    "gatsby": "4.10.2",
     "gatsby-image": "2.4.13",
     "gatsby-plugin-i18n": "1.0.1",
     "gatsby-plugin-manifest": "2.4.18",
     "gatsby-plugin-offline": "3.2.17",
     "gatsby-plugin-plausible": "0.0.7",
     "gatsby-plugin-react-helmet": "3.3.10",
-    "gatsby-plugin-sharp": "2.6.19",
+    "gatsby-plugin-sharp": "3.13.0",
     "gatsby-plugin-styled-components": "3.3.10",
     "gatsby-remark-check-links": "2.1.0",
     "gatsby-remark-images": "3.3.18",