[ODM-12773] Fix release notes for release 1.56

Author: Oleg Kunitsyn

…/deployment/release-notes/v1.50-v1.59.md docs/deployment/release-notes.mddocs/deployment/release-notes/v1.50-v1.59.md renamed to docs/deployment/release-notes.md docs/deployment/release-notes/v1.50-v1.59.md renamed to docs/deployment/release-notes.md

@@ -33,8 +33,7 @@ nav:
         - v1.30 - v1.39: release-notes/v1.30-v1.39.md
         - v1.20 - v1.29: release-notes/v1.20-v1.29.md
     - Deployment:
-        - Release Notes:
-            - v1.50 - v1.59: deployment/release-notes/v1.50-v1.59.md
+        - Release Notes: deployment/release-notes.md
         - Requirements:
             - Kubernetes: deployment/requirements/kubernetes.md
             - Hardware: deployment/requirements/hardware.md