Document that component names and versions should always be lowercase to avoid portability issues with different web servers

From Antora Gitter chat:

side note from poking around, the component name should always be lowercase (otherwise, you get portability issues with different web servers)

David Jencks @djencks_gitlab 04:10 thanks for the tip!

Dan Allen @mojavelinux 04:11 (same goes for the version)

David Jencks @djencks_gitlab 04:11 should antora warn if that's not the case?

Dan Allen @mojavelinux 04:13 if you know what you are doing, it isn't wrong. I've considered it, but that would likely be too restrictive. the docs should emphasize it though