Add the generated README.plain.md file to .gitignore.

Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
---
 .gitignore | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.gitignore b/.gitignore
index 4b86fff..4aab0f6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,4 @@
 /pasta.1
 /seccomp.h
 /passt.pid
+README.plain.md
-- 
2.37.2