SolidInvoice's user invitation tokens have no expiry, allowing indefinite unauthorized company access via leaked or old invitation links

SolidInvoice is an open-source invoicing platform. Prior to version 3.0.1, `UserInvitation` entities have no expiry timestamp. Invitation links mailed to users remain valid indefinitely, meaning a leaked, forwarded, or archived invitation email can be used at any time in the future to join a company or silently add a compromised email account to a company. Version 3.0.1 fixes the issue.