Serve/SPA: readFile returns EISDIR instead of ENOENT when a directory is called

[biboc]

Q	A
Bug fix?	yes
New feature?	no
BC breaks?	no
Deprecations?	no
Tests pass?	yes
Fixed tickets	-
License	MIT
Doc PR	https://github.com/pm2-hive/pm2-hive.github.io/pulls

When http://locahost:3000/category/tutorial---basics (Docusaurus example) is called, readFile returns EISDIR instead of ENOENT so the error "Sorry, check with the site admin for error: EISDIR" is showed

[biboc]

Travis.org to .com was changed automatically

[thadk]

Any update on this PR? I am seeing the same issue on SPA when wanting to use a folder as main site.