chore: fix CODEOWNERS (#200)

Change:
- Remove requirement for an @openebs/org-maintainers member's review when merging non-policy documents.
- Settings changes:
   - Mandate code owner approval
   - Ensure required approval is set to 1

Signed-off-by: Niladri Halder <[email protected]>

Author: niladrih

.github/CODEOWNERS

@@ -1,7 +1,6 @@
 # Default code owners
-*                           @openebs/localpv-zfs-approvers @openebs/org-maintainers
+*                           @openebs/localpv-zfs-approvers
 
-# CODEOWNERS file owners
 /.github/CODEOWNERS         @openebs/org-maintainers
 
 # Policy docs owners