Update CODEOWNERS (#676)

moving myself into only the /src folder. I end up getting too many
notifications for releases etc, but would still like to follow what's
happening inside the SDK.

.github/CODEOWNERS

@@ -48,7 +48,8 @@
 /packages/addresses/ @sergekh2 @texuf @giuseppecrj
 /packages/generated/ @sergekh2 @texuf @giuseppecrj
 /packages/generated/dev/ @sergekh2 @giuseppecrj
-/packages/sdk/ @sergekh2 @texuf @erikolsson
+/packages/sdk/ @sergekh2 @texuf
+/packages/sdk/src/ @sergekh2 @texuf @erikolsson
 /protocol/ @sergekh2 @texuf
 /scripts/ @texuf
 turbo.json @mechanical-turk