Update gitignore to ignore md files for AI agents

OpenStack uses .rst for docs, so .md files can all
be ignored, which covers the AGENT.md files used for
AI coding assistants.

Change-Id: Iebf485894c391a0f38d5a8314a79c1e3a41d6b7c
Signed-off-by: Emma Foley <efoley@redhat.com>
1 file changed