The IRS will fix this for you - you do not have to do anything.
If you already filed and did not claim the exemption for unemployment compensation, the IRS will refigure your taxes for you and send any refund that is due.
From the IRS: New Exclusion of up to $10,200 of Unemployment Compensation:
If you have already filed your 2020 Form 1040 or 1040-SR, there is no need to file an amended return (Form 1040-X) to figure the amount of unemployment compensation to exclude. The IRS will refigure your taxes using the excluded unemployment compensation amount and adjust your account accordingly. The IRS will send any refund amount directly to you.
