editorconfig: fix bad syntax

The proper indent_style value is "tab" not "tabs".

Link: http://docs.editorconfig.org/en/master/editorconfig-format.html#properties
Signed-off-by: Robin Jarry <[email protected]>

Author: rjarry

.editorconfig

@@ -21,13 +21,13 @@ indent_style = space
 indent_size = 3
 
 [Makefile]
-indent_style = tabs
+indent_style = tab
 indent_size = tab
 
 [*.sh]
-indent_style = tabs
+indent_style = tab
 indent_size = tab
 
 [*.{h,c}]
-indent_style = tabs
+indent_style = tab
 indent_size = tab