editorconfig updates

* Define `indent_size` so it will indent properly on VSCode
* `package.json` always uses 2-space indentation

.editorconfig

@@ -6,7 +6,10 @@ root = true
 # Tab indentation (no size specified)
 [*]
 indent_style = tab
+indent_size = 4
 
-[{.travis.yml,npm-shrinkwrap.json}]
+# The indent size used in the `package.json` file cannot be changed
+# https://github.com/npm/npm/pull/3180#issuecomment-16336516
+[{.travis.yml,npm-shrinkwrap.json,package.json}]
 indent_style = space
 indent_size = 2