Vitess Operator API Reference is stale

[yoheimuta]

README.md has a link to the documentation about CRD APIs implemented by the operator.

vitess-operator/README.md

Line 8 in 847bdc3

- [VitessCluster CRD API Reference](docs/api.md)

But the last time when this API document was updated was Aug 31, 2021.
So, it lacks a lot of recent information.

As CONTRIBUTING.md mentions the user-facing docs for the public API, wouldn't it be useful for OSS users to hook up with https://vitess-operator.planetscale.dev/api/ instead of the out-of-date markdown file?

vitess-operator/CONTRIBUTING.md

Lines 26 to 31 in 847bdc3

	### CRD API Documentation
	It may help to start by reading the user-facing docs for the public API,
	which can be found in `docs/api` or published at:
	https://vitess-operator.planetscale.dev/api/