build(deps): bump gatsby-plugin-mdx from 1.2.43 to 1.7.1 in /docs (#1615)

Author: dependabot[bot]

docs/package-lock.json

@@ -18,7 +18,7 @@
     "gatsby-plugin-emotion": "^4.3.10",
     "gatsby-plugin-google-analytics": "^2.8.0",
     "gatsby-plugin-manifest": "^2.9.1",
-    "gatsby-plugin-mdx": "^1.2.43",
+    "gatsby-plugin-mdx": "^1.7.1",
     "gatsby-plugin-netlify": "^2.3.13",
     "gatsby-plugin-netlify-cache": "^1.2.0",
     "gatsby-plugin-offline": "^3.7.1",