add editorconfig rule for json files

.editorconfig

@@ -6,7 +6,7 @@ indent_style = space
 indent_size = 2
 trim_trailing_whitespace = true
 
-[*.{js,css}]
+[*.{js,css,json}]
 charset = utf-8
 end_of_line = lf
 insert_final_newline = true

.eslintrc.json

@@ -33,4 +33,4 @@
         "location.origin"
       ]
     }
-}
+}

.stylelintrc.json

@@ -18,4 +18,4 @@
         "no-irregular-whitespace": true,
         "string-no-newline": true
     }
-}
+}