Site Maintenance: Update Dependencies

[rachelwhitton]

Upgrade Site Dependencies

• Upgrade Gatsby from 4 to 5 latest version and all packages to latest version, including stale dependapot PRs which are now closed and to be consolidated within this issue:
  • Bump postcss from 8.4.21 to 8.4.31 #8724
  • Bump word-wrap from 1.2.3 to 1.2.4 #8617
  • Bump semver from 5.7.1 to 5.7.2 #8606
  • Bump tough-cookie and node-sass #8602
  • Bump engine.io and gatsby #8526
  • Bump gatsby-plugin-sharp from 4.25.0 to 4.25.1 #8368
• Resolve all Dependabot alerts and unpause dependabot

Test Coverage

MVP for this may be a test that's run locally by hand as a first iteration, but we should follow up by exploring automation opportunities with dependapot

• Add VRT coverage for each of the following paths:
  • Docs home /
  • Landing (e.g., /certification)
  • Certification study guide (e.g., /certification/study-guide)
  • Doc (e.g., /core-updates)
  • Guide (e.g., /guides/mariadb-mysql/kill-mysql-queries)
  • Release note (e.g., /release-notes/2016/01/quicksilver-platform-hooks-are-now-available)

[rachelwhitton]

Closing this out so they can be worked out in the pr queue