chore: improve readme and docs (elixir-tesla#716)

Author: yordis

.editorconfig

@@ -0,0 +1,10 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+max_line_length = 80

CONTRIBUTING.md

@@ -0,0 +1,7 @@
+# Contributing
+
+1. Fork it (https://github.com/elixir-tesla/tesla/fork)
+2. Create your feature branch (`git checkout -b my-new-feature`)
+3. Commit your changes (`git commit -am 'Add some feature'`)
+4. Push to the branch (`git push origin my-new-feature`)
+5. Create new Pull Request

LICENSE

@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2015-2021 Tymon Tobolski
+Copyright (c) 2015-Present Tymon Tobolski
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal