chore: fix CODEOWNERS

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 <niladri.halder26@gmail.com>

Author: niladrih

.github/CODEOWNERS

@@ -1,5 +1,5 @@
 # Default code owners
-*                           @openebs/mayastor-approvers @openebs/org-maintainers
+*                           @openebs/mayastor-approvers
 
 # CODEOWNERS file owners
 /.github/CODEOWNERS         @openebs/org-maintainers