test: reduce max workers to prevent http 429 error

__tests__/jest.config.js

@@ -61,7 +61,7 @@ module.exports = {
   // globals: {},
 
   // The maximum amount of workers used to run your tests. Can be specified as % or a number. E.g. maxWorkers: 10% will use 10% of your CPU amount + 1 as the maximum worker number. maxWorkers: 2 will use a maximum of 2 workers.
-  maxWorkers: 2,
+  maxWorkers: 1,
 
   // An array of directory names to be searched recursively up from the requiring module's location
   // moduleDirectories: [