Kubernetes release v1.10.3-beta.0

Based on https://github.com/kubernetes/kubernetes/releases/tag/v1.10.3-beta.0
Merge pull request #60682 from hanxiaoshuai/update0302

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

update Mount propagation version in comment

**What this PR does / why we need it**:
Mount propagation feature was moved to beta in PR [#59252](https://github.com/kubernetes/kubernetes/pull/59252), so update the comment.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #60657

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```

Kubernetes-commit: a0844c17bfb964e3d1709784203e8404f790116c
tree: bd02f580562399e3af4533392660502163ad73fd
  1. .github/
  2. admission/
  3. admissionregistration/
  4. apps/
  5. authentication/
  6. authorization/
  7. autoscaling/
  8. batch/
  9. certificates/
  10. core/
  11. events/
  12. extensions/
  13. Godeps/
  14. imagepolicy/
  15. networking/
  16. policy/
  17. rbac/
  18. scheduling/
  19. settings/
  20. storage/
  21. code-of-conduct.md
  22. CONTRIBUTING.md
  23. LICENSE
  24. OWNERS
  25. README.md
README.md

This repo is still in the experimental stage. Shortly it will contain the schema of the API that are served by the Kubernetes apiserver.