Fix signup link in README.md

Author: LaundroMat

README.md

@@ -13,7 +13,7 @@ Accepting [iDEAL](https://www.mollie.com/en/payments/ideal/), [Bancontact/Mister
 ## Requirements ##
 To use the Mollie API client, the following things are required:
 
-+ Get yourself a free [Mollie account](https://www.mollie.com/signup). No sign up costs.
++ Get yourself a free [Mollie account](https://my.mollie.com/dashboard/signup). No sign up costs.
 + Create a new [Website profile](https://www.mollie.com/dashboard/settings/profiles) to generate API keys and setup your webhook.
 + Now you're ready to use the Mollie API client in test mode.
 + Follow [a few steps](https://www.mollie.com/dashboard/?modal=onboarding) to enable payment methods in live mode, and let us handle the rest.