IMP: formatting by keeping auth.json indent, same as composer

.editorconfig

@@ -16,3 +16,6 @@ indent_size = 2
 
 [composer.{json,lock}]
 indent_size = 4
+
+[auth.json]
+indent_size = 4

auth.json.sample

@@ -1,8 +1,8 @@
 {
-  "http-basic": {
-    "repo.magento.com": {
-      "username": "<public-key>",
-      "password": "<private-key>"
+    "http-basic": {
+        "repo.magento.com": {
+            "username": "<public-key>",
+            "password": "<private-key>"
+        }
     }
-  }
 }