build(deps): bump gatsby-source-filesystem from 2.3.30 to 2.8.1 in /docs (#1617)

Author: dependabot[bot]

docs/package-lock.json

@@ -34,7 +34,7 @@
     "gatsby-remark-images": "^3.8.1",
     "gatsby-remark-mermaid": "^2.1.0",
     "gatsby-remark-responsive-iframe": "^2.8.0",
-    "gatsby-source-filesystem": "^2.3.30",
+    "gatsby-source-filesystem": "^2.8.1",
     "gatsby-transformer-remark": "^2.8.28",
     "gatsby-transformer-sharp": "^2.9.0",
     "gatsby-transformer-yaml": "^2.4.11",