[Snyk] Upgrade gatsby-plugin-mdx from 2.6.0 to 2.15.0#393

mjperrins wants to merge 1 commit intodev-advancedibm-self-serve-assets/ibm-gsi-cloudnative-journey:dev-advancedfrom

snyk-upgrade-ead399b823af2dee8cd36a1c000f4855ibm-self-serve-assets/ibm-gsi-cloudnative-journey:snyk-upgrade-ead399b823af2dee8cd36a1c000f4855Copy head branch name to clipboard