.gitignore: don't ignore .github directory

Don't ignore .github special directory as it does contain specific files
for github CI workflows.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>

.gitignore

@@ -9,6 +9,7 @@ logread
 validate_data
 getrandom
 .*
+!.github
 Makefile
 CMakeCache.txt
 CMakeFiles