fix: upgrade @mdx-js/react from 1.6.19 to 1.6.22

Snyk has created this PR to upgrade @mdx-js/react from 1.6.19 to 1.6.22.

See this package in npm:
https://www.npmjs.com/package/@mdx-js/react

See this project in Snyk:
https://app.snyk.io/org/github-newrelic/project/f888c3c2-125f-4ff7-a0c6-0181b3c27c8b?utm_source=github&utm_medium=upgrade-pr

Author: snyk-bot

package-lock.json

@@ -8,7 +8,7 @@
     "@emotion/core": "^10.1.1",
     "@emotion/styled": "^10.0.27",
     "@mdx-js/mdx": "^1.6.19",
-    "@mdx-js/react": "^1.6.19",
+    "@mdx-js/react": "^1.6.22",
     "@newrelic/gatsby-theme-newrelic": "^1.16.3",
     "@splitsoftware/splitio-react": "^1.2.4",
     "date-fns": "^2.14.0",