Add EditorConfig (#7)

Author: anishathalye

.editorconfig

@@ -0,0 +1,14 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+indent_style = space
+trim_trailing_whitespace = true
+
+[*.py]
+indent_size = 4
+
+[*.toml]
+indent_size = 2