window.web3 is not offered anymore by metamask

[marcofranssen]

Code has to be migrated to new approach as documented over here.

https://docs.metamask.io/guide/provider-migration.html#replacing-window-web3

[Moeshrande]

Hi there, could anyone rewrite the code of this tip button to the current metamask situation? I keep getting errors... Would help me a lot thanks!