fixed opencollective link

Author: klues

ReadMe.md

@@ -59,7 +59,7 @@ If you want to support the development of AsTeRICS you're very welcome to donate
 <a title="Donate with PayPal" href="https://www.paypal.com/donate/?hosted_button_id=38AJJNS427MJ2" target="_blank" style="margin-right:3em">
 <img src="https://github.com/asterics/AsTeRICS-Grid/raw/master/app/img/donate-paypal.png" width=300/></a>
 <span>&nbsp;&nbsp;&nbsp;</span>
-<a title="Donate at opencollective.com" href="https://opencollective.com/asterics-foundation/projects/asterics-grid" target="_blank">
+<a title="Donate at opencollective.com" href="https://opencollective.com/asterics-foundation" target="_blank">
 <img src="https://github.com/asterics/AsTeRICS-Grid/raw/master/app/img/donate-open-collective.png" width=300/></a>
 </div>