Should be in the next release:
https://github.com/andikleen/mcelog/commit/2261c74a88f9bc9e87c9ffaae5a98261087730ae.patch

From: Andi Kleen <andi@firstfloor.org>
Date: Sat, 6 Nov 2021 07:22:24 -0700
Subject: [PATCH] Fix logrotate syntax

Fixes #102

Signed-off-by: Andi Kleen <andi@firstfloor.org>
--- a/mcelog.logrotate
+++ b/mcelog.logrotate
@@ -3,7 +3,7 @@
     dateext
     maxage 365
     rotate 99
-    size=+2048k
+    size +2048k
     notifempty
     missingok
     copytruncate