Add .editorconfig file and make Prettier use it

.editorconfig

@@ -0,0 +1,14 @@
+# http://editorconfig.org/
+
+# top-most EditorConfig file
+root = true
+
+# Formatting options. Note: Prettier also uses some of these.
+[*]
+end_of_line = lf
+insert_final_newline = true
+charset = utf-8
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 2
+max_line_length = 100

package.json

@@ -69,7 +69,6 @@
     "audit": "nsp check --preprocessor yarn"
   },
   "prettier": {
-    "printWidth": 100,
     "singleQuote": true,
     "trailingComma": "es5",
     "proseWrap": "always"