The issue is not with your Teams client, but with the invite link. I'm getting the same "update message" when trying to open your invite link.
You have the currently latest Teams Free application, and no update is required.
The "invite" link is actually not an invite, but links to a PHP site which prompts update of Teams regardless which version is currently installed.
Ask your "potential employer" to send a real invitation link.
https://support.microsoft.com/en-gb/office/invite-people-to-a-meeting-in-microsoft-teams-4bc5981c-446e-4e93-866a-d757466b556a
Be aware that because you have Teams Free personal account, and the "potential employer" might be on Teams for Business, you will only be able to participate in the meeting as a guest.
https://dori-uw-1.kuma-moon.com/en-us/microsoftteams/guest-access