Probably an incorrect URL in the description of the Maintenance Grant

[artem-radchenko]

Page with full description of the Maintenance Grants (https://github.com/eosnetworkfoundation/grant-framework/blob/main/docs/maintenance-grants.md?plain=1#L14) contains a link from the words "milestone delivery" that leads to the W3F Grants Program page https://github.com/w3f/Grant-Milestone-Delivery#mailbox-milestone-delivery-process , that probably is not relevant to the EOS Network Foundation Grant Framework.