doc CHANGE add editorconfig file

EditorConfig is a file format and collection of text editor plugins for
maintaining consistent coding styles between different editors and IDEs.

Initialize the file following the current coding style in existing
files.

In order for this file to be taken into account (unless they use an
editor with built-in EditorConfig support), developers will have to
install a plugin.

Link: https://editorconfig.org/
Link: https://github.com/editorconfig/editorconfig-emacs
Link: https://github.com/editorconfig/editorconfig-vim
Signed-off-by: Robin Jarry <[email protected]>

.editorconfig

@@ -0,0 +1,21 @@
+# ex: ft=dosini
+
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+charset = utf-8
+indent_style = space
+indent_size = 4
+
+[*.yml]
+indent_size = 2
+
+[*.yang]
+indent_size = 2
+
+[packages/debian.rules.in]
+indent_style = tabs
+indent_size = 1
+tab_width = 8