I know this is probably too late to be of any assistance, but I just encountered the same error.
The problem seems to be the use of user as a table alias (at least, that's the case for the instance i'm upgrading that is backed by postgresql).
The fix in this instance is simply to edit the auth/oidc/db/upgrade.php, at around line 74, and alter the sql statement to use a different table alias.
The query (as i've modified it) looks like:
SELECT u.id as userid,
u.username as username,
tok.id as tokenid
tok.oidcuniqid as oicduniqid,
tok.idtoken as idtoken
FROM {auth_oidc_token} tok
JOIN {user} u ON u.username = tok.username
WHERE u.auth = ? AND deleted = 0