fix: upgrade multiple dependencies with Snyk

Snyk has created this PR to upgrade:
  - @nivo/core from 0.78.0 to 0.87.0.
    See this package in npm: https://www.npmjs.com/package/@nivo/core
  - @nivo/line from 0.78.0 to 0.87.0.
    See this package in npm: https://www.npmjs.com/package/@nivo/line

See this project in Snyk:
https://app.snyk.io/org/sammytezzy/project/602a077e-0e5c-4a97-8c88-38c065da8ad1?utm_source=github&utm_medium=referral&page=upgrade-pr

examples/using-mdx/package.json

@@ -6,8 +6,8 @@
  "author": "LekoArts",
  "dependencies": {
  "@mdx-js/react": "^2.1.2",
- "@nivo/core": "0.78.0",
- "@nivo/line": "0.78.0",
+ "@nivo/core": "0.87.0",
+ "@nivo/line": "0.87.0",
  "@sindresorhus/slugify": "^1",
  "gatsby": "next",
  "gatsby-plugin-mdx": "next",