Update CODEOWNERS (ni#9)

Added Wai Kin as one of the owners as he needs owner's right to do
development for Github self-hosted runner.

- [X] This contribution adheres to
[CONTRIBUTING.md](https://github.com/ni/nisync-python/blob/main/CONTRIBUTING.md).

### What does this Pull Request accomplish?

Added Wai Kin as one of the owners as he needs owner's right to do
development for Github self-hosted runner.

Signed-off-by: CHrislian-NI <[email protected]>

Author: CHrislian-NI

.github/CODEOWNERS

@@ -1,2 +1,2 @@
 # These owners will be the default owners for everything in the repo.
-* @tkrebes @tsengguanyung @CHrislian-NI
+* @tkrebes @tsengguanyung @CHrislian-NI @wchung-ni