chore: remove Matt from CODEOWNERS so it stops erroring

we can readd him once he has accept the repo invite

Signed-off-by: Nathan Weinberg <nweinber@redhat.com>

Author: nathan-weinberg

.github/CODEOWNERS

@@ -2,7 +2,7 @@
 
 # These owners will be the default owners for everything in
 # the repo. Unless a later match takes precedence,
-* @cdoern @derekhiggins @Elbehery @leseb @mfleader @nathan-weinberg @rhdedgar @rhuss @skamenan7 @VaishnaviHire
+* @cdoern @derekhiggins @Elbehery @leseb @nathan-weinberg @rhdedgar @rhuss @skamenan7 @VaishnaviHire
 
 # These owners will own only CI and testing related infrastructure
 .github/ @Artemon-line @kami619