Add editorconfig to configure indentation

Patch adds a commit 'Add editorconfig to configure indents'
(886976a) that was implemented and the
reverted in scope of issue with discard v2.

Follows up #90
Part of #134

Author: ligurio

.editorconfig

@@ -0,0 +1,23 @@
+# top-most EditorConfig file
+root = true
+
+# Unix-style newlines with a newline ending every file
+[*]
+end_of_line = lf
+insert_final_newline = true
+
+[CMakeLists.txt]
+indent_style = space
+indent_size = 4
+
+[*.cmake]
+indent_style = space
+indent_size = 4
+
+[*.lua]
+indent_style = space
+indent_size = 4
+
+[*.{h,c,cc}]
+indent_style = tab
+tab_width = 8

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 - Replace Travis CI with Github Actions.
 - Add workflow that publish rockspec.
+- Add editorconfig to configure indentation.
 
 ## [2.1.0] - 2020-01-30