Fix indendation on devel/coding-conventions.md
Fix indendation on devel/coding-conventions.md

Fixing the indendation means the markdown will now render correcly on
Github.

Signed-off-by: Matt McNaughton <d0388760b91d86bb40e560651d9bf64323d45b23@gmail.com>

kubernetes/community,pwittrock/community,bgrant0607/community,bgrant0607/community,kubernetes/community,pwittrock/community,kubernetes/community