build(deps): bump gatsby-source-filesystem from 2.8.1 to 2.11.0 in /docs

Bumps [gatsby-source-filesystem](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-source-filesystem) from 2.8.1 to 2.11.0.
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-source-filesystem/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/commits/gatsby-source-filesystem@2.11.0/packages/gatsby-source-filesystem)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

docs/package-lock.json

@@ -34,7 +34,7 @@
     "gatsby-remark-images": "^3.11.0",
     "gatsby-remark-mermaid": "^2.1.0",
     "gatsby-remark-responsive-iframe": "^2.11.0",
-    "gatsby-source-filesystem": "^2.8.1",
+    "gatsby-source-filesystem": "^2.11.0",
     "gatsby-transformer-remark": "^2.13.1",
     "gatsby-transformer-sharp": "^2.11.0",
     "gatsby-transformer-yaml": "^2.8.0",